Old Pool to New Aquarium?

Oct 15, 2012
3
Greetings,
I have an in-ground, indoor pool that has been sitting empty for about 12 years. It’s a 30’ diameter circular pool with a uniform depth of 12’ (about 65K gal.), shotcrete construction with a plaster finish. The plaster has a lot of fine, hairline cracks with calcium deposits that have seeped through in places. Otherwise, structurally, everything seems in good shape.

A sump pump keeps groundwater from accumulating around the base of the pool (a hydrostatic relief valve was not installed when it was built). The building has stayed at a high enough level of humidity that the walls and base of the pool have stayed fairly damp. It has not been subjected to any freezing conditions. The water circulation fittings and piping seem fine, although a little ground water seeps into one of the two floor drains. The original pump, filter and heater have been junked.

I have serious notions of getting this beast up and running again, but as a freshwater tropical aquarium (!). I’m thinking 76-78 F., a few large fish and a couple schools of small fish, artificial plants, maybe sand on the bottom, etc. Swim with the fish or observe through the 4’ x 5’ observation window that’s already in place. I’m researching options for water filtration and treatment that would be appropriate to keep fish happy and healthy at the aquarium/fish sites.

My main question for this site is: What are my options for sealing/waterproofing the plaster finish in a way that is non-toxic, durable and not prohibitively expensive? I welcome any advice or attempts to talk me out of this notion before it becomes a monetary black hole.

Thanks
 
Replastering would be the most likely method of sealing the pool. If there were a better/faster/cheaper method to make a pool water tight, it would be used in place of plastering.

The conditions for healthy fish and plants are generally not suitable for human swimmers in a small container such as a pool.
 
You're suggesting removing the old plaster and then replastering?
My research suggests that with good filtration and UV treatment one could maintain healthy conditions for swimmers and fish. Can you cite any sources for your conclusion?
Thanks
 
Fish tale, do you have an aquarium now?
Maybe freshwater is completely different -- I had angles way back when but can't remember -- but I have a tropical salt aquarium with live rock, coral, etc.
The very first thing you do is cycle the water with bacteria. Via fish defication. Our water is dechlorinated before we add it. Our uv filter controls some specific pathogens that can infect the fish, but if it actually killed the bacteria, it would kill our live rock, which it doesn't. So I don't know that I would trust the uv with my health much more than say a squirt of garlic oil ;)

So, you've piqued my curiosity re:research that views these two uses as compatible. I'd be interested to hear more about that, actually.

In outdoor natural pools/ponds, I thought I had read that it was the plants/aquascaping that filter the water and keep it in balance. In your scenario, without the bio-equilibrium, is that what the uv is supposed to do?

It certainly sounds cool, but if it can be done, why not do a saltwater reef! It'd be like diving!
 
FishTale said:
You're suggesting removing the old plaster and then replastering?
My research suggests that with good filtration and UV treatment one could maintain healthy conditions for swimmers and fish. Can you cite any sources for your conclusion?
Thanks

Yes, a replaster is what we would suggest.

We would appreciate what is behind your research as we are all heare to learn. To the best of my knowledge neither fish, plants or UV are registered with the EPA as a primary residual sanitizer suitable for swimming pools. What may work in nature with large bodies of water is not the same as a small indoor swimming pool.
 
Hi again. I was just chatting with my husband, who is big into aquariums, so I thought I'd share some of his observations. You may have already worked this stuff out -- just asking ;)

In his aquarium he's turning the water completely 3-4 times an hour. Perhaps that's a density issue, and if you had a low fish density might not be as much of an issue, but he was wondering what al you'd have to do to the pool to get the kind of turnover filter times needed for the population -- which as you know, will grow.

He was surprised about artificial plants because beautiful species like cichlids love to feed on live plants, and the plants also help oxygenate the water.

We were also wondering what you might rig up for adequate oxygenation as a bubbler system, because it'd need to be pretty massive for 65k gallons!

Two other issues would be a large backup generator to run it all in the event of power outage (trust us on this one, we've had our hearts broken) and possibly a chiller depending on how you were able to manage both the ambient heat and machine heat. Depending on your location, there'd also be the possibility of heating required.

I realized you asked a single question and instead of answering it I'm asking you a boatload of question, but it's an interesting idea and I'm curious.

I'm also curious about what kind of fish you were thinking about getting.

Now, with regard to your question:
As far as repairing the surface without resorting to re plastering, I'm wondering if two-part epoxy would work if
the cracking wasn't too bad. I've worked with it for outdoor art installations and once cured, it's waterproof and doesn't outgas to my knowledge. I believe the make a type for pool leak repair that actually can cure
underwater, so if it doesn't outgas too much to be legal for humans, hopefully the same would hold true for fish!

Lots of folks use lexan and acrylic to construct aquariums, and in terms of components, they're essentially resins too.
 
Kevin, what's in Herculiner? Is it by chance epoxy? I know you can expoxy-treat garage floors and they're pretty indestructible!

Then again, I just meant to epoxy coat the hairline cracks, which would be cheaper, just to get a good seal. If he were going to cover the surface entirely, wouldn't a 20 mil liner be cheaper than a replaster or epoxy coat?
 

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FishTale said:
You're suggesting removing the old plaster and then replastering?
My research suggests that with good filtration and UV treatment one could maintain healthy conditions for swimmers and fish. Can you cite any sources for your conclusion?
Thanks

To be healthy for swimmers, there needs to be residual sanitizer in the water to prevent transfer of pathogens. UV doesn't provide that.
 
I saw a pond thread about a couple in Houston that converted an IG gunite pool into a pond that was just beautiful. Converting an indoor pool to an environment for fish is one of the crazier ideas I've heard (and I like crazy).

For plants you will need direct sun or lights which will heat up the space something fierce and you will soon have an algae ridden mess so you won't be able to see the tropical fish you added.

The converted pool to koi pond can work outside but for an indoor pool, I think you would just have a tough time with it.
 
Crazy, but intriguing ;) I know with h's saltwater tropicals, we need light ballasts, and they do dramatically add heat (hence the need for the chiller). His lights include a "moonlight" setting because apparently the fish need to tell night from day or they get stressed ;) His ballasts were pricey and are older now -- I'm given to understand that some folks are using LEDs instead nowadays, which dramatically reduces the heat generated. But I don't know if any of this applies to freshwater fish. Nor do we know what kind of skylight/windows etc. are in the location...
 
dmanb2b said:
FishTale said:
You're suggesting removing the old plaster and then replastering?
My research suggests that with good filtration and UV treatment one could maintain healthy conditions for swimmers and fish. Can you cite any sources for your conclusion?
Thanks

Yes, a replaster is what we would suggest.

We would appreciate what is behind your research as we are all heare to learn. To the best of my knowledge neither fish, plants or UV are registered with the EPA as a primary residual sanitizer suitable for swimming pools. What may work in nature with large bodies of water is not the same as a small indoor swimming pool.

First, think of this primarily as an aquarium. With good water treatment via mechanical & biofilters and UV (granted this would not be cheap given the volume to be treated) it should be possible to maintain crystal clear water and a healthy environment for fish. The building allows almost no exposure to natural light so I would not initially include live plants because of the lighting requirements, especially given the depth of the water. The density of fish would be minimal compared to the volume of water.

As for swimming with the fish (no more than 2 or 3 people at a time), this is a private pool and I'm aware of no laws or codes that would mandate that a chemical residual be maintained. No one monitors our private pools & spas and there are non-chemical options out there for "regular" pools (http://www.bionovanaturalpools.com). I think one could create a swimming environment cleaner and safer than almost any given lake or pond in which people swim.

Regarding the plaster, it finally dawned on me that losing some water is not a problem and actually takes care of a need in maintaining an aquarium. Even with a low density fish population there is the need to regularly replace a portion of the water to prevent the buildup of nitrites. I don't think the leakage rate would be excessive, but I'll need to fill it to find out. This just leaves a concern about calcium deposits that might adversely affect the pH.

I appreciate all the posts and will try to get to any questions that I haven't answered.
 
The major difference you are going to have to handle is the suction on the inlet side of the pump. In a pool, rapid and strong water flow into the skimmer is wanted because it helps clean the surface of the pool. With fish, you'll need to mechanically restrict the fish from getting near the inlet to keep them from being pulled into the skimmer or drain or trapped against the protective screen.
 
FishTale said:
dmanb2b said:
FishTale said:
Regarding the plaster, it finally dawned on me that losing some water is not a problem and actually takes care of a need in maintaining an aquarium. Even with a low density fish population there is the need to regularly replace a portion of the water to prevent the buildup of nitrites. I don't think the leakage rate would be excessive, but I'll need to fill it to find out. This just leaves a concern about calcium deposits that might adversely affect the pH.

I appreciate all the posts and will try to get to any questions that I haven't answered.


I am not sure what sort of structure this pool is in - A 12' deep 30' round pool in a room with minimal natural light? The only thing in my head right now is an old water tank that was designed for watering live steam locomotives that was converted into a warehouse that I once worked on. Think a huge square concrete tank that rose 5 feet out of the ground. They slapped a roof on top, cut a hole in the side, built a ramp inside - and bingo! now it's a warehouse.

Anyway, back on topic, depending on what type of structure this is in, I would be worried about what the leakage is doing to my foundation.

-dave
 
I'm all about dreaming and thinking outside the box but this just seems unrealistic unless you are willing to go all in. The time and money to get it going and then to maintain it would be way beyond a hobby status. I have a 14 gallon biocube salt water aquairium with 2 fish some snails and whatever hitchhikers came along on my live rock. It involves a lot of work to keep it healthy and clean for the inhabitants. Like Swampwoman says there are water changes, climate controll, mechanical and biological filters, food, die off and all the other stuff that comes long with it. I would say take a trip to the local zoo or aquarium and see if you can get a behind the scenes tour to see all the stuff it will take to manage your aquairium. Also think of the smell and funk it would create if worse came to worse and you had a massive die off at some point, which happens a lot from what I've read.
It would be awesome to see some pics of what you are working with.
 
FishTale said:
dmanb2b said:
FishTale said:
You're suggesting removing the old plaster and then replastering?
My research suggests that with good filtration and UV treatment one could maintain healthy conditions for swimmers and fish. Can you cite any sources for your conclusion?
Thanks

Yes, a replaster is what we would suggest.

We would appreciate what is behind your research as we are all heare to learn. To the best of my knowledge neither fish, plants or UV are registered with the EPA as a primary residual sanitizer suitable for swimming pools. What may work in nature with large bodies of water is not the same as a small indoor swimming pool.

First, think of this primarily as an aquarium. With good water treatment via mechanical & biofilters and UV (granted this would not be cheap given the volume to be treated) it should be possible to maintain crystal clear water and a healthy environment for fish. The building allows almost no exposure to natural light so I would not initially include live plants because of the lighting requirements, especially given the depth of the water. The density of fish would be minimal compared to the volume of water.

As for swimming with the fish (no more than 2 or 3 people at a time), this is a private pool and I'm aware of no laws or codes that would mandate that a chemical residual be maintained. No one monitors our private pools & spas and there are non-chemical options out there for "regular" pools (http://www.bionovanaturalpools.com). I think one could create a swimming environment cleaner and safer than almost any given lake or pond in which people swim.

Regarding the plaster, it finally dawned on me that losing some water is not a problem and actually takes care of a need in maintaining an aquarium. Even with a low density fish population there is the need to regularly replace a portion of the water to prevent the buildup of nitrites. I don't think the leakage rate would be excessive, but I'll need to fill it to find out. This just leaves a concern about calcium deposits that might adversely affect the pH.

I appreciate all the posts and will try to get to any questions that I haven't answered.

I agree there is no law or regulation for a private pool, other than in cases where an abandoned pool becomes a health risk to others (ie mosquitos, etc) and never suggested it is required. Heck no one is stopping me from swimming in my toilet bowl :smile:

However the post I replied to stated "healthy" conditions for both swimmers and fish. I also read your first post that the idea here is not only to achieve that in a pool, but indoors to boot. Perhaps the end result will yield you an environment "safer" than a pond or lake or even seawater, but the are not as safe as a properly sanitized pool, with a residual sanitizer, whether it required by law or not or not. Biofiltration and UV alone will not protect the swimmers in this case from risks such as a Cryptosporidium infection, Legionellosis, influenza or even athlete's foot. You could argue that the UV treatment could eliminate the risks I mentioned, but you would have to ensure 100% of the water is being treated by UV, at a minimum on a daily basis. To even come close to acheiving 100% filtration, you would have to turn the pool over 3-4 times and at 65K gals I feel that will be difficult and expensive to acheive.

If money is no object, then perhaps a system can be devised (I will not claim to understand even where to begin) but I would imagine the cost would be high enough, that the cost of a replastering would be immaterial as compared to acheiving "healthy" conditions for both swimmers and fish.
 

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