WATER QUALITY IN MARINE MAMMAL EXHIBITS

Panel Discussion at the Ninth Annual Conference of The International Marine Animal Trainers Association, Niagara Falls, USA. October 1981.



CHAIRMAN:

Ed Krajniak
Brookfield Zoo

PARTICIPANTS:

Al Clifton
Aquarium of Niagara Falls, USA

John Dineley
North Wales, Great Britain

Austin McDevitt
Minnesota Zoological Garden

Greg Siebenaler Gulfarium

Dr. Jay Sweeney
Palos Verdes, California

Dr. Sweeney started the discussion with an overall view of water quality and filtration systems. The remaining panel members then followed, telling about the water quality and filtration systems they deal with in their oceanariums. The main topics addressed were as follows:

1) Total gallons of water in system
2) Type of filters used
3) Water turnover rate
4) Type of salt used -if artificial
5) Salt level maintained in pools
6) Make-up water added per day
7) Chemicals added for clarity and bacteria control
8) Types of test kits used to monitor chemicals
9) Do they monitor for nitrate, nitrite, ammonia?
10) Bacteria, fungus, yeast or coliform tests

JAY SWEENEY, D.V.M.: My business being here is to provide you with an orientation on water quality. Basically, to bring us all up to a basic plane of knowledge so that as we talk further with the various panel members we will all know what we're talking about.

Most of us are quite aware, I think, that we have problems with water if we don't treat it in some way. As our knowledge of water quality treatment becomes more refined, we're finding that there are probably as many problems that come from over treating as those that come from under treating and so it's very important that we refine our knowledge and that we create this fine center point which provides for good quality water, while not creating a problem with animals when doing so. Well, what are we trying to do with water in treating it? Basically, there is removal of particulates, removal of biological wastes, control of microorganisms, control of algae, removal of organic and inorganic colors, and providing homeostasis in a variety of other aspects.

The end result, of course, is to maintain water that is healthy for the animals, and water that looks good, because most of our animals are in a fishbowl exhibit type of setup.

Removal of Particulates doesn't provide much of a problem for most of us. Many of us use some form of filtration, at least mechanical filtration; pressure filters, diatomaceous earth filters and/or gravity filters. But there are other forms of particulate removal including flocculents, activated carbon. Ozone, which we'll discuss through most of this discussion this morning and afternoon, also is a substance useful in removing particulates, but it has many more uses besides.

As we go along we're going to note that whatever your treatment of water, the most advantageous situation, of course, is water exchange. If you can change your water, if you're Marineland of the Pacific, if you're Seaquarium, any of these places that are on the coast, this is by far the most advantageous means of water treatment. So most of our discussion is for those of you who must deal with water in a closed system.

Removal of Biological Wastes is, of course, among the primary reasons for water treatment. To elucidate a little bit on wastes, what are the basic wastes we're talking about? We're talking about feces and urine, but for the sake of discussion, we can look at waste as nitrogen, or, more specifically, as ammonia. Animals excrete ammonia and this is the primary biological waste that goes into our water systems.

The basic method of removal of biological wastes is through a process called oxidation. We oxidize the wastes away. This is why we use many of the chemicals that we use; chlorine for one. So what we're trying to do, and we're going to go through a bit of chemistry, really very, very basic chemistry, is we take ammonia, and we oxidize it through chemicals or other methods, basically to nitrogen, to oxygen and hydrogen, as free hydrogen or as water. If all goes well, this is what we're doing. Nitrogen blows off as gas, the oxygen blows off as gas or mixes into the water, and the hydrogen goes to create pH and also goes off as gas. That's the ideal situation to get rid of ammonia.

Now the problem is that this is the ideal situation. When we're adding chemicals to get rid of ammonia we can start creating problems. The most common oxidant, the chemical we're using to oxidize the waste products away, of course, is chlorine. The problem with chlorine is that chlorine combines with the nitrogen to form byproducts, which, of course, are chloramines. So instead of going directly from ammonia to nitrogen and oxygen, ammonia combines with chlorine and goes to chloramine, which is NH2CI, dichloramine (NHC12) and trichloramine (NC13). These are the primary problem products of our attempts to oxidize ammonia to its harmless by-products. The basic point then, of course, is that we oxidize ammonia away.

There are three basic methods of using chlorine in water treatment. One is low concentration; very low levels 0.2_3 parts per million of chlorine. Break point chlorination, which is basically a high dose chlorine maintained as free chlorine, attempting to avoid the combination of chlorine into the chloramine groups. The last method is chlorine used as a shock treatment; that is to say, extremely high, potentially toxic high levels of chlorine to completely blow out any ammonia-nitrogen groups present.

We've all had experience with chlorine and know that there are problems with chlorine groups. So what other means of oxidation procedures do we have in order to remove ammonia? The other, and probably coming into use now more than anything else, is the use of ozone. Some of you are beginning to use ozone. Ozone is 03; it's a charged oxygen, by nature of the extra oxygen group. Normally oxygen is 02. If you put one more oxygen molecule on there it's 03. It very quickly reduces to 02, giving off an oxygen, which is a strong oxidant, and thereby directly reduces ammonia to its basic products of oxygen and nitrogen. The problem with ozone at the present time is, we don't know yet what the toxicity of the stuff is, and the more important problem, I think, as we perhaps get into the discussion through the panel, is the maintainability of ozone production units. It's an extremely good oxidant, very effective in removing the waste products, but the problem is can we get the units to work well enough to make it functional? Sea World has been using ozone for a number of years now in large concentration units. The fact that makes ozone more readily available to most of us nowadays is that companies are beginning to produce ozone units in portable generators that are inexpensive. We're finding that very low levels of ozone are adequate in order to control many of the nitrogen products. We don't any longer need very heavy concentrations. Ozone's a real potential water treatment mechanism.

One of the aspects of waste removal, which is just now coming into some use in mammal systems, is the one that's been used in aquarium systems for many years, very effectively, and that's biological filtration. Very few organizations have adopted biological filtration in a large degree in mammal systems. New England Aquarium has it to a small degree, and some that are being designed now are beginning to have it planned for use in marine mammal systems. Basically, what we're doing is we're asking a bacteria to do the basic work that we've been asking chlorine to do, and ozone to do, for so long. What happens here is, if you have your ammonia, you expose it to oxygen aerated water and bacteria. The bacteria converts the ammonia to nitrite which in itself is fairly toxic. But what happens to the nitrite is more bacteria and oxygen convert it to nitrate so that the nitrate is non-toxic. So that we can take a system with no treatment whatsoever, providing we provide a substrate for bacteria to grow, and we circulate the water through that substrate, much like the bottom filter in an aquarium.

There are more efficient means, like what's being done in sewage treatment plants nowadays. We can, in effect, remove these biological wastes from the water with no other form of treatment, whatsoever. The problem is that it's a delicate system, it requires a lot of delicate handling and it is unproven as yet. I think you're going to hear more about biological filtration in the future. It has, I think, a role in mammal water treatment systems. But we'll wait and see what kind of usage it gets.

Activated carbon: we also don't hear too much about activated carbon. It's another one of those agents that's used in fish systems a lot. Carbon has a very nice property, and that's that it's a very porous substance. Water circulates through it well and it also has a property of being attracted to just about anything chemical in the water. It removes nitrogen, it removes ammonia, it removes practically anything from the water providing water can circulate through it and all the pores in the carbon are not already filled up by stuff that's passed through. Carbon has a real potential not only in fish systems, but also in mammal systems, in that it is very effective in cleaning out a lot of this stuff and, in effect, has no effect on water, besides at that point when the water circulates through it. The problem is that it's expensive, it's heavy when you have to deal with it in the filters, and it's a bit cumbersome to work with. However, again, it produces no toxic side effects and we like that very much.

So there are a lot of ways of dealing with biological wastes. Not just chlorine, which we have used in the past. We've got ozone, we've got the biological filtration, we've got activated carbon and there are several others, in fact, coming up through the research mill that may give us some relief from the problems we've all experienced with chlorine. Keep your eyes open, keep your minds open to the idea of new treatment systems for handling biological wastes.

Control of microorganisms really is the second basic important factor in treating water. Bacteria tend to build up if the water's not purified in some way. They build up because animals are defecating feces that are rich in bacteria. Bacteria builds up, because animals are secreting biological wastes, which serve as good nutrient bases for bacteria to grow. So, if we're going to recirculate water, we need to have some way of dealing with bacteria, obviously. One of the myths in aquatic systems management, with mammals at least, has been that we need to sterilize our water. Most of us, I think, know now that this is not true. In fact, it's a harmful type of thing to achieve. We'd like to have a balance of bacteria in the water, just keeping the bacteria down to some reasonable low level, and that level has been established through regulatory channels at 1,000 col if orms, which are fecal bacteria, per 100 mi I I ileters (m Is) of water. Most of us would rather see our water a little bit better than that. I think if I had to pick an ideal bacteria count for water, I would look at something like 100 coliforms per per 100 mls of water which is just fine for keeping that balance between bacteria, fungi and all the rest of the things that are in the water.

At any rate, we need to control microorganisms and how've we been doing this? We've been doing it with chlorine. Obviously, chlorine is not only a strong oxidant for dealing with ammonia wastes, but chlorine is also a strong anti-bacterial, anti-fungal, really strong anti-fungal, chemical. But, of course, we already discussed that chlorine presents a considerable amount of problems. So what else do we have to use in dealing with bacteria problems? Well, you might have guessed the next alternative, of course, is ozone. Ozone not only is an extremely good oxidizer of biological wastes, but it's also even perhaps more effective in killing bacteria. The problem with ozone is that it's probably too good at killing bacteria, and the only saving grace to ozone is that, the way that it's applied in most systems, it will dissipate rapidly and by the time it gets out to the main tank where your animals are, they continue defecating and they keep a supply of bacteria living in the tank. Ozone does have some potential here in the control of microorganisms. Well, what else? Copper. Copper has been used but copper is not very effective in controlling bacteria. It has its own toxic by-product. Copper is a livertoxin, and we have enough liver problems as it is. We don't need to add to it with copper, although copper is commonly used in many aquarium and oceanarium systems. What else is going to control bacteria for us? Quaternary ammonium (Q) compounds have been used in the distant past, but are rarely used today.

Ultra-violet (UV) light: some aquarium systems have been using UV light. I think the Niagara systems have been using it. Mystic, I think, has used it in some respects. UV light is very toxic to all living organisms, bacteria, virus, fungi. The problem with UV light is that in the size systems that we're talking about, which is normally 100,000 gallons and larger systems, you need contact time with UV light and you don't have the time. Putting water through UV light filters to get that contact, and get back out to the tank in order to maintain your two to four hour circulation times is a problem. So UV light is good in small systems under 100,000 gallons. Going into larger systems, UV light just isn't set up to do the job under the technology that we currently have.

Biological filtration has an indirect role in the control of microorganisms because, don't forget, some of the microorganisms that we have in our systems come from the nutrient base that the ammonia provides. So if we can control the nutrient base by using biological filtration, we avoid the substrate upon which bacteria grow. We can thereby indirectly limit the number of bacteria that are allowed to grow in the system. It's not effective when we've got a large amount of feces going into a system, but in a low volume system, low animal load system, perhaps biological filtration has a significant effect. Of course, water exchange is the best way to get rid of the bad water and exchange it for new, good water if we have the luxury of being near a good water source.

Control of algae: Many of us who deal with systems that are exposed to sunlight have algae problems. Speaking of algae, it's an interesting phenomenon of water systems, particularly closed systems, that none of them are the same. You can say, "Well, we need to break point chlorinate this system-, we need to provide ozone to this system, we need to do this, and do that," and what works for one system, we found, doesn't necessarily work for another system. It's almost uncanny to look at the same volume of water, the same basic visual circumstances, where one has an algae problem, the other has a bacterial problem, or none at all. So as we talk, you should be reminded that each system is independent, separate and somewhat fickle in its own way. We oftentimes need to find the best way for our system, and take what we can from the information that's provided by other systems.

Algae's a real nuisance because, of course, it turns our water green and it makes it unappealing to look at. Algae itself has no toxic effect upon animals, and, in fact, the only potential health risk that algae provides is, when it dies, it provides more nitrogen base for combining with chlorine and potentially is a substratefor bacteria to grow and consume oxygen. But basically, algae isn't a health risk problem. It's purely a visual, esthetic problem. Chlorine is a reasonably good algaecide. Chlorine in large enough concentrations will take care of most of your algae problems. Of course, the problem with chlorine is that it combines with the by-products of algae, the dead algae, combining into chloramines and again we have the chloramine problem that plagues us with chlorine.

Another problem with chlorine is that algae tends to develop a resistance to it gradually so that as time goes by, year after year, we need higher levels of chlorine in order to maintain some sort of level of control over algae. So chlorine in itself is fine, but be careful, over long periods of time, of the problems that are going to come with it. Well, ozone is very effective against algae. It kills it extremely efficiently. A problem that we're having with ozone is that we're beginning to use it in some of these closed systems, small closed system oceanariums, 70,000 gallons to 200,000 gallons. We find that we get good contact with algae in the pipes where the ozone is discharged and where the action occurs, but by the time the water gets around and back out into the tank, most of the ozone is dissipated and gone. Which is what we want because ozone is potentially toxic. We don't know how toxic, but there's always concern for that. But when you get out to the tank, your ozone is dissipated pretty much, and all your treatment which took place in the pipes is no longer taking place in the tank. Therefore, you have basically untreated water exposed to sunlight, if you're in direct sunlight. The systems that are using ozone as their basic treatment mechanism, and are in direct sunlight, have a problem with algae. The algae, although it's killed immediately as it goes through the ozone contact, gets out in the tank and multiplies like crazy and the ozone doesn't control it out there where your animals are all swimming around.

So many times when we're dealing in these small systems, we need to add some other form of treatment and there are a number of them. One, of course, is copper and copper is a very efficient, strong algaecide; very effective in killing algae. But the problem with algae and copper is that, again, the algae becomes resistant to it. It takes more and more and more and more copper in order to kill the algae. When we get into higher levels of copper, one part per million or higher, we're getting into the range where we don't know what effect that copper has on the livers of our dolphins and sea lions. Because of this, we are concerned about the use of copper in high concentrations and for a prolonged period of time.

There are other algaecides. There's this new one, Simazine or Algi-Gon, which is becoming very popular. It's being used in fish systems extensively for dealing with algae and it's a very effective algaecide under certain circumstances. We're finding that if you take a tank that's green, pea green, and put Simazine or Algi-Gon in there it really doesn't do the job. But we're finding that Simazine is a good preventative against the buildup of algae in the first place. In other words, we get into a deal where we have a basic acceptable starting point; our water's clean, we're using ozone and we start our water circulating. We add our Algi-Gon at that point and maintain a level of Algi-Gon for a certain period of time. The algae tends to be prevented from growing and that seems to be an effective use of that chemical. Where we think we're going in the control of algae in ozone systems is using combinations of substances, using ozone with chlorine for a period of time, switching over to ozone with copper for a period of time and intermittently changing our form of algae treatment and, thereby, preventing the buildup of resistance among the algae organisms that are present.

Removal of organic and inorganic colors: Those of you who deal in closed systems have perhaps experienced water that turns somewhat of a greenish color. Treatment for algae doesn't seem to have any effect on it. What that appears to be is a very complicated, hi-molecular weight chloramine. We talked about chloramines as being monochloramin, dichloramines and trichloramines, but when a chlorine combines with ammonia or with other nitrogen groups, it not only forms the simple mono-, di- and trichloramines, but also form many different kinds of chloramine-nitrogen molecules. One of them appears to be a very large one which produces this green color and it's nearly impossible to get it out of there and it's been a real headache. There now appear to be several ways of taking that color out, that I can share with you. One, of course, which we talked about, is activated carbon. It takes out, as we said, virtually any chemical that happens to be in the water, including chlorine, copper or anything else that happens to be there. Activated carbon will take out many of the organic and inorganic color producing agents that wind up causing us so much annoyance in these close systems.

But again, in dealing with activated carbon, we're dealing with a bulk substance, something that's difficult to deal with once the active sites in the carbon are utilized. Here, I think, the most effective anti-color agent is now ozone. And we've gone through ozone, ozone, ozone, ozone. But ozone is going to be, and is, one of the most effective means of water treatment, providing that we can deal with some of the maintenance problems with it. Ozone is extremely effective in oxidizing away the inorganic and organic color producing chemicals in the water and has a very big role in the future of water treatment. Looking at ozone in this particular instance copper doesn't have much of a role here. Copper in itself is a coloring agent and it's just going to add to our problems. Mechanical filtration: diatomaceous (DE) earth filters do not work. Generally, most of the color producing agents are molecular in size and will go right through a DE filter, so most of these kinds of things are unaffected by most of the mechanical filtration. And, of course, if we can change our water we have the advantage of doing that and getting rid of the bad stuff. The removal of organic and inorganic colors is not so much of a problem any more, providing we have the ability to do it with carbon or ozone, and stay away from chlorines we can at all.

Homeostasis then: basically, we want to provide a system that is stable. If our system is bouncing up and down-, high chlorine, low chlorine-, copper, no copper-, high ozone, low ozone all this business-, we're never going to achieve our desired effect. We want to have a system that's the same, always the same. If we can achieve that, then the animals are basically going to adjust to it and be fairly healthy as a result. Maintain, as much as possible, a constant temperature. As much as possible, have control over salt concentrations: we can control that and we should. Sea water is 3.5% salt. Most closed systems manage their salt somewhere less between 2.6% and 3.0%. But whatever you choose, maintain it somewhere at a constant level pH has an effect upon chlorine and chloramine. We didn't even get into pH. pH has a important effect on these things and should be maintained as steadily as possible.

Water hardness: If we're using the HTH, the calcium hypochloride should be watched. Calciur is one of the hardness salts, that when put into the water produce some of the calcium salts thz are in effect similar to soaps and are potentially there to precipitate into white or gra substances. Hardness affects the clarity of the water and hardness is one of the things we don look at very often, but I think we should. In adding HTH to our systems, we're constantly addin calcium, and we're potnentially leading ourselves down the road to precipitating some of thes calcium salts that are potentially going to give us problems down the road. So we've got t consider what we're doing when we're adding these chemicals and what effect they're going t have upon the ultimate results in the long run.

We're going to go to John Dineley now and lie's going to give us a rundown on Europ systems.

JOHN DINELEY: Okay, I wrote this all out on the plane across, so it's a bit in note form, so I hope you'll excuse me. In introduction, I'd like to say that, although I've been primarily a trainer of marine mammals over the last eleven years, because of the ways European zoos and oceanariums run, I always had direct dealings with the water treatment care of my charges from understanding chemical water tests through to stripping down filter units themselves. I would briefly like to relate the situation as I see it in Europe in general and in the U.K. (United Kingdom) in particular with regard to water treatment systems. Most of the U.K. systems are closed systems. Only one facility has an open system which runs from sub-beach filters, positioned below the high tide mark. The use of DE filters was very popular in the early 1960's, in the U.K. It has now completely died out: so as far as I know there are no systems in the U.K. operating with DE filters anymore, although in Europe they still do use them. Sand filtration is now the major type of filter used. Mainly standard pressure filters running us about 200-250 gallons per square foot per hour, and high rate filters running at 1,000 gallons per square foot per hour; sometimes more, sometimes less. Now those of you who read my article in the last issue of Soundings on the presentation I gave at the last European Association for Aquatic Mammals meeting, on filtration, will be aware of my bias against high-rate filters. However, I must re--emphasize that my criticism is aimed at badly designed systems. I know of at least one large oceanarium which uses high-rate filters on their show pool to good effect. However, these have been well designed and have proper backwash facilities. It was, in fact, the cheapness of the small fiberglass high-rate filter systems which led to their wide use in the U.K. While we're on this subject, it's interesting to note that a very good rapid gravity filter system can be homemade. A colleague of mine at the University in Denmark has a system he built himself, some years ago, in operation for containing harbor porpoises, which works very well. There are not many good water treatment systems in operation in Europe. We still have systems, which have standards one would not expect from the present state of the art of aquatic animal husbandry. Common problems are poor filtration, low turnover rates, high animal to water ratio, and excessive chemical additions. Now, in my opinion, the first requirement for good water treatment has to be good filtration, with correct animal to water ratio in combination with a reasonable turnover rate. The minimum standard for animal to water ratio as calculated by Anderson, which was published in Aquatic Mammals, was 100 cubic meters per Tursiops; in my opinion, a minimum requirement. This is in a closed system, of course. Unfortunately, it has been my experience that excessive use of chemicals, such as chlorine, are being used to compensate for the lack of aforementioned requirements very much to the detriment of the animals. In fact, I'd go so far as to say that if a system is using more than 2 or 3 parts per million of total chlorine to maintain a system in check, the system probably fails in one, if not all, of the fundamental requirements. Well, this has been a very brief run through of my opinions of water treatment systems. I hope they haven't been too negative. I've stayed clear of detailing my own water treatment methods and practice in hopes that I can answer specific questions from the floor.

Al Clifton will now tell us about the system at the Niagara Falls Aquarium.

AL CLIFTON: I think most of you have probably had the opportunity to see our system. If not you'll certainly get the opportunity tomorrow at the wine and cheese party. Our system is fairly basic, built in 1965 and, at the time, the feeling was DE was probably the best system going. We have approximately 100,000 gallons in our pool. It's a circular pool. We have four filter bay areas in the back, each has a manifold that houses 35 filter cores, so we're looking at about 6 square feet of filter area per core. We've got about 840 square feet of total filter area for the whole system. Turnover rate'. we're looking at about once every 100 minutes, so a little bit less than two hours. We have two really good pumps that put out 500 gallons a minute, apiece. The salt we use is just a brine solution of bulk Purex salt. In the pool we try to run a specific gravity that fluctuates between 1.018 up to maybe 1.022; it averages about 1.020. Make-up water due to backwashes probably runs about 10% a week. Each of our filter bays holds approximately 15,000 liters or a shade under 4,000 gallons. Each set usually has to be backwashed about once a week.

As far as chemical additions go, we use chlorine. Our chlorine is what most people use, sodium hypochlorite, 15% solution. We do not meter out chlorine into the pool, we use hand addition. Metering is certainly a lot easier to handle, but the feeling on the hand additions is that it does not allow for constant levels of chlorine, so you do not get algae that tends to build up a resistance to certain low levels of chlorine. By adding chlorine maybe twice a day, in larger amounts you are, in a sense, sort of "mini-shocking" the system each time. While that certainly may be true, I'm not sure, as far as the animals' welfare is concerned, that's necessarily the best way to do it. We find in our system that we tend to get a chlorination which is essentially what water treatment facilities used to use. I have not, for as long as I can remember, ever been able to get a free chlorine reading on our system, ever. We use a LaMott DPD test kit that breaks it down into free chlorine and your chloramines that Jay was talking about. We deal almost totally in monochloramines, dichloramines and hydrogen trichlorites, which probably, in the long run, isn't the best system. Certainly, the free chlorine is much more effective as far as bacterial elimination goes. The chloramines certainly last much longer in the systems, but the free chlorine probably is about 25 times more efficient as far as a disinfecting agent.
We try to maintain our pH with additions of muriatic acid, which is technical grade hydrochloric acid. We drop our pH down to about 7.0, the feeling being that at low pH's the reaction is going to tend to slide more heavily towards free chlorine than it does at the higher pH's once you get up around 7.8-8.0. The reaction tends to go towards the less active chloramines in this situation so we try to keep our pH at the Aquarium down around 7.0. Whether or not that's been effective, it's difficult to say. Whether or not we are creating free chlorine and that the free chlorine is just acting so rapidly with the ammonia products that are in the water and immediately dissipating out, we have yet to determine. We do know that we have seen much better results in our bacteria samples since we started pH control about 4 years ago. So it has worked for us up to date, and we've seen no need to discontinue it.

We floc with alum. You usually have your choice of alum or ferric chloride. We use alum even in our DE system. What we try to do is to add about one-half pound of alum a day. We tried other levels but we try to use the least amount of alum that we feel is necessary to achieve the desired clarity in the system. That's worked fairly well. The other thing we do is we add some levels of activated charcoal to the system. What we also have is a slurry system that has a small pump that meters DE and charcoal continuously to these filter bays. What we don't want to have is our DE filter bays set up and then gradually the filters become clogged, and the reading on the gauges start to run up, and you start to get cavitation of your filters. We generally add a little bit of DE and a little bit of charcoal every day, to keep afresh layer on the filters, and that seems to help quite a bit. You can easily overdo it, you can add too much DE over a period of time, and you find that your filters just clog up way too fast, and few things are worse than incurring the wrath of the maintenance department. That's something that we learned long ago and something you don't want to do. As far as levels go and rates of addition, we tend to keep our chlorine level, our total chlorine level, let's say at .5 to probably a maximum of 1.0 parts per million. Like I said, that's strictly all chloramines in that reading. There's virtually no free chlorine whatsoever.

We add our chlorine, like I said, twice a day, so we're averaging maybe two gallons usually over a period of time, per day, as far as chlorine goes. Muriatic acid: we find it doesn't take very much to keep the pH at 7. We add about 1 gallon of acid a day for 100,000 gallons, that's a lot. It usually doesn't take very much more than that. I mentioned we use the LaMott DPD test kit. We've found that that's relatively accurate. We used to use an old ortho-tolidine test kit and we did not find the results to be particularly accurate. We usually run our tests twice a day; in the morning and afternoon. We'll monitor temperature which tends to run about 26°C on an average. We'll monitor temperature, we'll monitor specific gravity, we'll monitor pH and chlorine, maybe we'll make our alum additions or we'll do that in the afternoon. We do not have anybody that works on the evening shift or, for that matter, a midnight shift, that has the background for making additions at other times of the day. So what we have to do is just make certain that when we add chlorine in the afternoon, that level is going to maintain itself pretty much through the night and that we don't come in the next morning and find we have no clarity, a large algae bloom, and you have to root through the waterto find the animals again. That has happened. That's the one drawback to hand additions; if somebody's in a hurry to go somewhere, let's face it, it does slip your mind, you forget the chlorine addition and you usually pay for it the next day.

The problems that we've seen in our system are usually what most everybody else sees, at least as far as DE filters go. We suffer from short filter runs. We may run three or four weeks before we have to shock-treat the water. When I first started working at the Aquarium, we would probably have to do a superchlorination every three months. Now we find that we have to do them almost every three weeks. The load on our pool has not increased appreciably, though we may have an extra 100 pounds of animal in the pool, and we may be feeding an extra 10 or 13 pounds of fish a day, but that certainly would not account for such a drastic change. I certainly don't want to point fingers at this stage of the game but the city of Niagara Falls does suffer from certain maladies in its water that most other places, fortunately, do not have to put up with. As it is now, we were checking the water today and we're starting to find inordinately high levels of copper in our drinking water. I've talked to one person who just tested his water on Friday and he was getting 3.0 parts per million out of his tap. We're getting somewhat less than that, but certainly it's something that you want to be concerned about. Our major problem is the water in the Niagara River is less than pure. In 1979, the city was requested to switch their water intakes to a different part of the river which tends to be very limey. We get very high carbonate readings in our water now and that leaves us with alot of problems. When we make up our synthetic sea salts, we cannot run a batch of instant ocean salt anymore without first having to run it through diatomaceous earth filters to clean it up. We get extremely high alkalinity readings in our water. Whether or not that has any effect on our system, I don't know. The eye irritation we've seen is certainly a result of the chloramines, and the green coloration we've run into in our system is the same thing that Jay was talking about. We've tried in certain instances to get rid of it, assuming that it was algae, without success. It could very well be, as Jay says, that ozone is going to be the coming thing. We tried UV light before I worked here. I know they've used it at Mystic and, for the purpoises that Jay was talking about, I did not feel that it was a very good system. I just don't think that on our size system the contact time was there. I really hate to knock UV systems in general, but, at least in our system, it did not work. What works on our system may not work in another system. There certainly are generalities involved, but I don't think you can concretely say that you have to do A, B and C to get clean water-, there are just too many variables involved. I've always felt that as long as what you're doing has worked for you in the past and your animals seem to be healthy enough, well then that's fine: maybe it'll work for me, maybe it'll work for you, maybe it won't work for anybody, but you just have to go with what works for you.
For a coliform test we use a Millipore membrane filter test. We have levels from 100-150 colonies per 100 ml. We also, just as a matter of note, mark down the total plate count and the total coliform count so that we can check over our records and see if one tends to be fluctuating more than the other. If anybody has any questions on our system, if you don't want to talk about them now, I'll be over at the Aquarium so feel free to call any time.

Austin McDevitt will now talk about the Minnesota zoo

AUSTIN McDEVITT: We have two marine mammal systems at the Minnesota Zoo. We've also got two fresh water aquatic mammal systems. I'm going to concentrate primarily on marine mammal systems. If anyone has any questions about the beaver and otter systems, I'd be happy to answer them later. We have a beluga whale exhibit. It's a system that runs about 500,000 gallons of water; that includes the exhibit pool, the holding pool and the volume of water that's contained within the piping and filter chambers. Our dolphin exhibit contains about 90,000 gallons of water. This, again, is artificially manufactured salt water. We add sodium chloride to our water system to produce the desired levels of salt. In our whale exhibit we maintain the salt level between 1.5% and 2.0% salt. In the dolphin exhibit we maintain the salt levels at 2.0% to 2.5% salt. The reason that the whale exhibit specific gravity, or salt content, is lower than that of the dolphin is because, when we were out capturing our whales in the Hudson Bay and Churchill River area, we did take water samples up there and these are the approximate levels of salt that we found in Hudson Bay. The filtration systems that we have on both of these systems are high rate sand gravel filters, The whale filtration system contains eight filter chambers. We pump approximately 1,200 gallons a minute through each of the filter chambers, which gives approximately 576,000 gallons of water being filtered just about every hour. So we're turning over the entire volume of the pool within every hour. On our dolphin exhibit we have two sand gravel filters and we're pumping approximately 450 gallons per minute through that particular filter system, which gives us about 72,000 gallons per hour. So we turn over the entire volume of that system every hour and fifteen minutes to hour and a half. The only make-up water that is added to either of these complexes is the water that's used in backwashing. We backwash the filters through a reverse pumping procedure. Water is pumped from the exhibit through the filter and the water coming from the filter is then dumped. It takes approximately 6,000 gallons of water to do that. The wasted water is then made up with fresh water and then we also add salt to that to bring the specific gravity levels to where they should be. The backwashing is done on the basis of a differential pressure on the filter chamber each day. It usually runs every other day for the various systems. So that we have some filters being backwashed on one day and others not being backwashed.

The chlorine levels that we maintain in our pool are as follows: our free chlorine levels will run anywhere from 0 to .04. We hold our total chlorine levels in the whale pool to no more than 1 part per million and in the dolphin pool we keep it at .8 parts per million. The reason for that is that we've found that the dolphins, at least in our system, get eye irritations if we get above .8 parts per million. So we maintain the level in the dolphin pool lower than we do in the whale pool. The type of tests that we perform on a daily basis in both systems are temperature readings, free and total chlorine, pH, specific gravity and nitrogen ammonia levels. On a weekly basis we test for nitrates, nitrites, phosphates or phosphorus, reactants, sulfates, total hardness and turbidity. On a monthly basis we also do aluminum, copper and iron testing. The reason for this is because the water that we are using is very high in heavy metals and in calcium. We have a lot of calcium in the water that we're using in Minnesota. We also send out a number of tests to an independent testing company on a quarterly basis to be run for us, and there's a whole range of things that we test there, primarily for our own information to see if the well water is okay.
The equipment that we use for most of our water quality testing in-house is a Hach electrophotometer for getting our different levels. We have one of these at the dolphin holding area, it's a portable electrophotometer. Down in our veterinary lab we have a stationary electrophotometer and the lab techs primarily run these tests in the morning. If there is a problem, we then monitor the levels in the pool on an hourly basis. We do total and fecal coliform counts twice a week. We use a membrane filter technique, a standard lab method. We also use Millipore coliform supplies, but it seems that our lab method is superior for coliform recovery. I think that's about it on our pool.

What we have been doing at the present time is looking into an ozone system. We looked into it before the zoo opened but at that time, as Jay was saying earlier, the technology was such that the systems were rather large and had operational problems. In the past several years the technology has been improved and the systems are much smaller, compact and more inexpensive to purchase. There have been some problems with the maintenance of these systems, and at the present time, we are waiting for more information on the maintenance cost of these systems before we purchase one. We have, from time to time, if we have a buildup of nitrites in our whale or dolphin system, tried some shock treating with chlorine. Primarily what
we've done is shock treat the holding pools. We're able to isolate our holding pools from our main exhibit pools and we shock treat the holding pool over a period of 24 hours. With a bubbler in the back pool we burn off the excess chlorine, so that the remaining water can then be mixed with our regular system. This has worked very effectively for us in dropping down the biological levels in the pool. It does run into an expensive proposition if you do have to do this every couple of weeks. I think that's about it for our system.

We're going to go to Greg Siebenaler now from Fort Walton Beach and he'll give us some information on an open water system.

GREG SIEBENALER: Hi. I guess the reason I was asked up here is to show you just how easy some of us have it. We have four cetacean pools. We use only Atlantic bottlenose dolphins. Each pool has its own filtration system and heater hooked to it. During the summer months, when our water is very warm, we constantly run raw sea water through our systems and it's also being filtered simultaneously through a filter design that we came up with at the Gulfarium 26 years ago. It's a sand filter with three grades of gravel in it. We can turn over 1,500 gallons a minute through the filter. It's very high rate and works very well. Our pinnipeds all have their own small filtration system which is a small, commercial, rapid-flow filter. I personally don't like it at all because of the buildup of excretion, body oils and fish oils that seem to clog these systems up. So these pools run constantly, year-round, on their own open system.

The only chemical we use at the Gulfarium is chlorine and it's used more as an algaecide than anything else just to keep the algae growth down in the tanks. We're bringing in 1,500 gallons an hour to all of our pools so everyone's always getting new water all the time, plus it's being filtered. In the winter months we cut the cetacean pools down to where they're only getting raw sea water for make-up after backwashing our filters and we have to start regulating our chlorine levels a little bit more closely. We use the hand addition method for adding chlorine. Each man is responsible for his own area. It's very simple, it works well, it's designed to be done at certain hours during the day so that you don't run into the problems of someone running around at the end of the day because he just got a date or something. So it seems to work out pretty well for us.

We have coliform tests taken as required in our state. It's done by an independent testing lab who comes in during specific hours but unexpectedly and they do their own sampling. That way we don't have anyone in our organization trying to make his area look better by throwing chemicals in it just 30 minutes or so before people come to test water. We have found that this has happened.

We only change the regulation of chlorine an average of twice a year due to the sunlight that we have there. During the summer months we have 16 to 17 hours of sunlight a day. We chlorinate twice a day. But because the water's being taken away all the time, we don't have a chlorine buildup. Chlorine doesn't stay in our system more than about an hour, or two hours at most. In a nutshell that's just about it. If anyone has any questions, I'll be happy to answer them later.

ED KRAJINIAK.- I would like to talk about the system we use at the Brookfield Zoo. Our building was the first inland dolphinarium built in the country. So when they set it up they really didn't have any idea of what was going on. We have two systems. One houses our five bottlenose dolphins that holds 200,000 gallons of water. We have three California sea lions, a harbor seal and a walrus in a system that holds about 65,000 gallons of water. Basically, the same thing is done to both systems. The water that we use is a combination of lake water (Lake Michigan) and well water. The combination will change depending on the Zoo's usage of water. The filters we use are diatomaceous earth, vacuum leaf type filters. It's a pretty decent system; we haven't had any real problems with it. The turnover rate of the water is about every hour and a half in both systems.

The salt that we use is Morton bulk Purex but we've tried many types of salt and they all work pretty well. From Morton Salt we've used pure table salt, we've used bulk Purex, we've used water softening crystals and water softening pellets. We've also used International Salt Company solar salt, and the salt worked very well. The only problem we had with the salt was that you might get coral in it, wood chips and things like that, so it was creating problems in our salt holding tank. If the tank was designed a little differently you could use solar salt quite efficiently. The salt is very cheap. We paid about $25.00 a ton. We use an awful lot of salt, because we maintain a 31/2%, by weight, salt content, which would be about 1.025 specific gravity. Our building, automatically through the filtering system, changes 10% of the water every day. So we add 20,000 gallons of water a day, and it's a fresh, salt water mixture. We use between 15 and 20 tons of salt every week, so that adds up to quite alot of salt. It gets kind of expensive.

When they designed our building, they copied the Miami Seaquarium and Marineland of the Atlantic operations. These places would naturally flush the water through because they had the ocean right there. The people who designed the building had no idea what they should do, so they figured it was best to flush the water and, basically, that's how they designed the system. So that's the biggest difference between our system and any other system, other than an open system that is right next to the ocean.

The chemicals we add are chlorine or sodium hypochlorite. We use bottles of Clorox, a 5% solution, as opposed to a 15% solution. We also use a chemical that's a stabilized chlorine dioxide, and we've been using it for about twenty years. We use about four gallons of sodium hyochlorite and about two or three quarts of the chlorine dioxide a day. We meter the chlorine into the pools over a 24-hour period so it's constantly going in through a small metering pump that's on a timer. By metering the chlorine in over a 24-hour period the level of chlorine stays pretty constant in the pools. We floc our tank by using ferric chloride. We use a quart of ferric chloride that is pumped directly into the tank. It goes in at midnight and it's filtered out by our DE filters in about three to four hours. Because the water's being flushed through the tank pretty fast, we maintain the pH the same as whatever the pH is of the Park water that's coming into the pool. The pH ranges between 7.5 and 7.8. If the pH drops to 7.4 or 7.3 we will add a little soda ash.

One other thing that we're experimenting with was the use of an algaecide. We have been using small amounts of Simazine to control the algae growth. It seems to work but, after three months of use, it looks like we may have resistant algae strains building up. We maintain a combined chlorine level of about .09 - .11. If we go higher than .3 in our system we start getting eye irritations. We test the chlorine twice a day with a Hach ortho-tolidine test kit. We never get a free chlorine reading at all. Probably because we are at such low concentrations. We test the water for coliform by using a Millipore coli-tester. The total count will range anywhere from 0 to 70 colonies per 100 millileters.

To move back to chlorine testing for a moment, we have never been able to get readings with a DPD chlorine test kit in our pool. We're not really sure what ties it up, but the readings will always be off the scale. Instead of that usual red color that you get, it turns yellow or orange, and there's nothing you can compare the color with. The Hach test kit we use has two solutions, ortho-tolidine and sodium arsenite. We take one test using the indicator ortho-tolidine and we use that as a total. Then we take another sample: we mix sodium arsenite into that, which totally dissipates the chlorine. Then we add orthotolidine to the sample. You get a lower reading which is an interference reading because all the chlorine is gone. So we subtract that from the first reading and that's what we use as a total chlorine reading. With this method, or any other method, we've never been able to get a free chlorine reading at all. We have taken samples and have taken them right over to the lab. They'd run them and the readings would be the same as what we would pick up with the ortho-tolidine test kit.

We do not really monitor nitrite, nitrate or ammonia very much. Because of the fact we're pumping a lot of water through our system, we usually get zero readings for everything. The highest nitrate reading recently has been ten parts per million. Nitrite could go anywhere from one part per million to two or three. So we're dealing with very small amounts.

As I said before, we run coliform tests and we test for fungus and yeast. We use a Millipore test sample mode. It's a very simple test. We also send them out to the lab. In our case the Millipore unit is right on the head, we've never had any problem. It seems to be exactly the same as what we run into when we get the regular lab test back. That's about it for Brookfield Zoo. Does anyone have any questions for the panel?

QUESTION: You're always talking about algae in the pools. Why don't you have divers scrub it off?

ED KRAJNIAK: In our pool we have divers go in to clean off the algae. We use about 50 tanks of air a week. The problem is that the algae is always growing fast and you are never really able to get ahead of it. We find that when we scrub the algae, the chlorine level in the pool drops to zero, because the algae floating in the water uses it up. This causes a build up of chloramines and you have to add a lot more chlorine to get up to the level you are trying to maintain which also causes more chloramines. If you could use an algaecide to keep the algae down, without any harm to the animals, you could also use less chlorine. You would have less organic material in the pool that would combine with the chlorine, causing a build up of chloramines.

KAYCE COVER: I have three questions for Jay. I would like to ask him what kind of schedule or how much attention has been given to the scheduling of how you dose with algaecide? For example, at the National Zoo we had problems with using an algaecide along with chlorine because together the two things form an insoluble green precipitate and we had green polar bears and it wasn't March. So that was a big problem. Another thing is, with using activated charcoal with any kind of water system, if you're also using chlorine, won't you be working against yourself? Unless you dose with chlorine and then let that dissipate, how would you account for that? Finally, I had heard of some new research on the way chlorine affects fatty acids in the skin and this might account for some of the fungal diseases that people with closed systems have been experiencing.

JAY SWEENEY. Well, starting from the third on down, chlorine's affect on fatty acids; we don't know really what, specifically, is the effect chlorine has on skin as it might relate to the onset of fungal diseases. No doubt there is some effect because it's just unreasonable to think otherwise when we see fungal diseases coming up in closed systems oceanariums where there is a high use of chlorine and high chloramines versus open systems where there's relatively low use of chlorine and we virtually rarely see any kind of Candida infections. So undoubtedly there's an effect of chlorine or chloramines on skin and it may be directly on the fatty acids of the epidermis. So there is probably a relationship there. We don't know what it is as yet and you're probably more informed than I am at the present time on that.

As far as carbon versus chlorine is concerned, yes, carbon will take the chlorine out and the idea of using carbon is that if you're using carbon all the time, if it's one of your treatment units, you're not going to be able to use chlorine. However, there's all sorts of uses for carbon and/or ozone with chlorine systems in an alternate type of a setup. If you're going to use carbon in a chlorinated system, the idea is to use it only in alternate periods to get rid of the chloramines and chlorine and everything else that's built up as an alternative to shocking your tank. But if you're going to use it with chlorine on a continual basis, you're really fighting yourself and defeating the purpose of chlorine in the first place.

With algaecide versus chlorine producing the green color, I don't know. Chlorine does funny things with other compounds. No doubt you've produced a pigmented molecule that's similar to these high molecular weight chloramine compounds. There's no point in using algaecides with chlorine. What the point was, is in controlling algae using algaecides independently, but in succession, alternating them; chlorine being one, algaecide being the other. I would like to see an ozone system whereby you would alternate with chlorine for a week, go to Simazine for a week, go to copper for a week, and do this kind of alternating so that you're not mixing any two algaecides. You would be using these things independently so that we're not allowing any of these developing resistance and tolerances on behalf of the algae to these various algaecides, which we do see, and which is, no doubt, happening with Ed at Brookfield. The point with chlorine is, chlorine is a strong oxidant. It's going to oxidize most anything you put in there with it and in doing so, it's going to combine with that substance and produce something. That something may be a color producing agent like chloramine or like whatever it is that's produced your green coloring on the polar bears.

MARK SHAWVER: Three basic questions flocculation, pros and cons-, if you use alum is there any buildup and problems later on? Second, total alkalinity: can you get to a toxic level? We generally use gas chlorine, therefore, we have a battle to keep the pH raised, so we're using soda ash. We use soda ash as opposed to baking soda which I've done some reading on, but I've never heard of it used with aquatic mammals. We believe that using soda ash tends to raise the total alkalinity and I'd like to have a response on total alkalinity and if there is a toxic level of total alkalinity.

JOHN DINELEY: Well, if you're trying to use something like soda ash to raise the total alkalinity you're wasting your time. The only way you're going to raise the total alkalinity is basically to add sodium bicarbonate. That will raise your total alkalinity. Things like sodium carbonate will not affect it in any way whatsoever.

MARK SHAWVER: The problem is the opposite. Our total alkalinity increases over months. So what I'm asking is, is there a point where anybody thinks the total alkalinity gets to a dangerous level? The point is, we don't feel it's a problem, but we go from city water which is down to about 100 parts per million and up to about 1,600 now. We don't see any effects,i but we're just concerned.

JOHN DINELEY: What's the water coming in at? What's the total alkalinity of the water that's coming into your system?

MARK SHAWVER: Well, it's about 100 or 120.
JOHN DINELY: And what kind of chlorine? You use gas chlorine? And you've got total alkalinity going up to 1,600?

MARK SHAWVER: Well, that's because of soda ash, we believe. That's the only place it would come from.

JOHN DINELEY: Possibly. If there were impurities in it might be. I don't know from the point of view of the animals, but if you start going above, say 200 total alkalinity, you're going to create problems for yourself with your machinery to start with. I would say that if you are using gas chlorine, I would expect the reverse problem, that you wouldn't be able to maintain total alkalinity. You'd have to keep adding sodium bicarbonate and sodium carbonate at a certain rate to maintain total alkalinity around about 100 or 150 parts per million. That's about the range that's in the ocean.

MARK SHAWVER: But how are you going to lower this? If you use muriatic acid, for instance, you're going to lower your pH.

JOHN DINELEY: You will lower it momentarily, over a short period of time, but you'll find your pH will go up again afterwards. The thing is you've got to do it over a long period of time. You can't just start throwing acid in and expect it to go down in two or three days. This thing has to be spread out over a period of months. Especially if you've got a very high total alkalinity. You'll probably do untold damage to your machinery and animals if you try and throw loads of acid in, so it's got to be over a period of time. But you'll find that, generally speaking, your pH will start to come up again, which is the whole point of the total alkalinity. If you've got none there at all, your pH will tend to go up and down like a yo-yo with whatever alkaline or acid you're at. Once you've got the total alkalinity balanced at a certain level, you will tend to find your pH will stay very much the same. But, of course, remember your animals, and you will add chemicals into the system which are going to alter the water anyway. But you do have a problem, a unique problem, with total alkalinity getting too high.

AUSTIN McDEVITT: In reference to the flocculation question, what kind of filters do you have? We have two systems -DE high rate and gravel.

In floccing with alum, we've found in sand and gravel filters that what we originally tried to do is shut down the system, the filtration system, floc the pool, and then go in and vacuum out the sediment on the bottom of the pool when everything settles out. The major problem we had is that the flocculant following floccing, when it sets on the bottom of the pool as a precipitate, is more of a heavy liquid precipitate. It doesn't precipitate out in a crystalline form, so when you try to vacuum it, as soon as you get near the bottom of the pool, it just all blows back up into the water.

So what we did was to simply turn on our filtration system and then just keep a close watch on the filters, so that when we got a differential pressure, we'd immediately backwash. If you get too much of a flocculant in a sand and gravel filter it's going to bind up the sand and you're going to have channelling in your filter and won't be filtering anything at that point. I don't know in a DE filter system. I think you could really foul up the sleeves in a DE filter with a flocculant.
AL CLIFTON: It can be done, though. We use alum as a flocculant out on our DE filter and I haven't really seen a problem. If you added slowly and evenly, or if you could set up a system where you just had it dribble in ahead of your filter, you don't run into any problem with DE filters.

AUSTIN McDEVITT: I want to add one more thing in regard to the sand and gravel filters. One thing that we do in Minnesota for additional clarity is that, after backwash, we coat the upper level of the sand-gravel filter with a medium called "Crystal-Flow" which is basically an artificial diatomaceous earth. It's a manufactured product. We probably put about 1/2 inch on top of each of the filters. The way we do this is that it's pumped into the filter and we found that by doing this it increases our clarity probably a hundred fold.

SHERYL WEAVER: This is on flocculation with alum again. We had some sand and gravel filters in our system and we've been adding alum to our filters the same way you just described with this; Crystal Flow and, when you add your alum to the pool, is that with the animals in the pool?

AUSTIN McDEVITT: No.

JOHN DINELEY: I just want to say that when you're using alum, you've got to be extremely careful because if it gets into the water and your animals are present in the water, alum at very low concentrations will be extremely irritating. In fact, maybe much of the eye trouble that is sometimes attributed to chlorine is, in fact, due to the fact that too much alum is in the pool.

SHERYL WEAVER: In the way that we're adding our alum then, putting it right into the rapid sand and gravel filters, do you think that most of it is passing through the filters before we flocculate?

JOHN DINELEY: It depends on the flow rate of your filter. If you're using high rate filters, there's a good chance it will just go right back in the pool.