Could use some advice on Huge DIY Concrete tank

[LouieM]

Down in my basement I have 4 finished rooms. A huge living room, a bathroom, a laundry room, and the kicker what was supposed to be a fish tank room. This fish tank room is shaped like a sidewise "L" with the bottom of the "L" being about 10 feet wide. Without any real research I decided to build a huge concrete tank.

Too make a long story short I built a massive concrete tank 9 feet long, about 7 feet wide, 4 foot high. I purchased a 2 1/4 inch think sheet of acrylic for alot of cash. Anyhow, I still shiver at that cost. Following the guidance of a local fish store guy ( Ok I now know they haven't a clue on what they are talking about) He said take a ruber pond liner, line the inside of the tank, cut out the viewing area and then anchor bolt the glass to the front. There is about a 6 inch lip all the way around the front of the tank. To make another long story short it leaked. The pond line idea blew chunks. That was over 3 years ago and that tank room has stayed closed off to the world.

Now I have learned about the internet and come along ways in my knowledge and reading about these wooden tanks I think I can easily make this work now. The epoxy paint sounds great. I allways thought the paint would leach chemicals into the water is why I never thought of this.

Any words of advice on how to apply the paint? Anything before or after? There is no way the tanks frame or that space shuttle thick pice of acrylic will break. My main fear is just sealing the edges of the viewing panel. Any advice will be great.

[SaltwaterNovice]

LouieM:

You can use epoxy paint to seal the concrete walls.

You do not need to bolt the acrylic to hold it in place. Everyone that I am aware of that has a concrete tank has a notch or lip around the opening that the acrylic seats into. Picture a picture fitting into thre lip of the picture frame.

Use lots and lots of silicone between the lip and acrylic to seal.

There are three people that I am aware of that have constructed large concrete tanks.

First, Richard Harker has a 2000 gallon concrete tank that was featured in the 2002 annual edition of Marine Fish Magazine. Great article for planning and equipment ideas.

An update article was recently published in one of the online reefkeeping e-zines. I can not find a web site for this tank and would love more information on it myself.

Second, Mr4000 buiolt a 4000 gallon tank in his basement but removed it due to humidity damage the tank was causing to the house. You may want to investigate that issue to prevent that problem. He had a website but I believe that he took it down.

Third, Rbells constructed a 1000 gallon concrete aquarium. He has thgoroughly detailed the construction of his tank and included lots of pictures His cite is a great source for how to construct a concrete tank and install an acrylic pane.

Please post more details and some pictures of your project.

There are lots of helpful people that will jump in with ideas and advice.

Hope this helps,

Good Luck,

Brian

[LouieM]

Thanks for the advice. Do you know the link to Rbells sight? I have done some searches but no luck. I never thought of humidity issues but I am sure there is some solution if it becomes a problem.


Louie

[MarkS]

Not to add insult to injury... You could have gone with 1", 1 1/4" or 1 1/2" thick acrylic without any problems...

It's the total height of that tank that determines the thickness of the glass or acrylic. 1" would be minimum at 4' high.

[The Aquarist]

I am no expert at this stuff, but here are my thoughts and some links:

This website may help you out alot:
http://www.cichlid-forum.com/articles/diy_1700g_tank_1.php

It isn't a concrete tank, but it explains how this guy resolved a few of your questions. I would be nervous about using his method of glass placement, but I believe Mr 4000 did the same thing with a leak the first time and no leak after using much more silicone the second time. Mr4000.com. That was a good website

I am wondering why you would need to seal the concrete. As long as it has no cracks and you let it cure for a couple of months until your ph returns to normal, I think you'll be ok. Mr. 4000's site is down, but I don't remember him sealing the walls. I could be wrong, but I think it was just concrete with internal rebar because of the height. I am nearing the end of a home made rock cycle, where it's taking a couple of months of soaking in fresh water (and I drain and add new fresh water every day to keep the water from becoming calcium saturated and stopping the curing process) to return to normal fresh water pH.

The articles I read on curing cement and aragamax mixed rock said that the cement should be cured in fresh water first and when the cement stops leaching forms of calcium at dangerous levels, the ph drops to safe levels and then the same curing method is recommended for 2 weeks with salt water.

You can check out an article here:
http://www.geocities.com/CapeCanaveral/Hangar/6279/RaiseCementRock.html

If you used an unsafe (for reef tanks) cement mix to make the tank, you could probably coat the inside of the tank with a 2 or 3 inch layer of a Portland/Aragamax mixture and cure it.

Just some quick thoughts there. Good luck.

[leykis1o1]

well it really depends on the size i build conrete structures all the time including ponds and fountains made from concrete...if the concrete structure is going to be holding salt water you must use a specific re-bar made for this application its coated in plastic and have never had to use it but i know of it since i took a Concrete Specific Class in College so i think its Green Plastic Coated rebar...you also will need to Thoroseal the inside..its a concrete product made just for the purpose of re-taining water ususally used for ponds and fountains including Sea World uses it all the time....after your done thorosealing your basin your going to need to leach the concrete of it "toxins" do water changed several times a weak for some period of time .ive heard people doing this to make live rock with concrete so my guess this applys the same...if it was just Fresh water i wouldnt worry about leaching since i know nobody does this...but as to Corals are so delicate to toxins doing a few water changes after you build it woyuld be a good idea...maybe even a few water tests..

[MarkS]

Mr. 4000 let his tank cure for six months.

I don't remember if he sealed it or not. I do think that if the walls were epoxy coated you would only need to let the epoxy cure. That should just take a couple of weeks after the epoxy has hardened.

[LouieM]

Awsome, Thanks for the info. I will epoxy coat the walls and do some more research on the front acrylic.

Yeah, when I saw how thick the sheet of acrylic was I figured I coulda went thinner. That was 3 years ago ( Back when I thought the local fish guy was the end all of knowledge about fish) After I had a leak he then just shrugged his shoulders basically and I haven't been to that store more than twice since.

But with this expoy solution I think I'll have my tank up and running within 6 months or so.

Its most likely going to be freshwater though. I love my saltwater set up, but the cost of live rock and the lights to make to it work would cause my wife to go on a warpath. Plus I allways wanted to get a few of those amazon fish( red tail cat, pacu,ect...)

Thanks for the advice

[leykis1o1]

if its going to be Freshwater dont bother epoxy coating it....i build these all the time and man im telling you Thoroseal is all you need....ive never had one fail yet and this is what is done throughout the industry

[The Aquarist]

You don't need to buy all of that live rock! You can make most of it yourself! Nice BIG pieces! Caves! Tunnels! The fish hotel! The link I posted earlier explains it. You can probably make the least expensive mix with Portland cement (roughly 5 bucks for 80 Lbs.) and a bunch of Southdown Tropical Play sand. AND, IF YOU ACT NOW .... Play sand is cheaper than it would be in the spring or early summer! When you are done and ready to run the tank, just add a few pieces of real live rock and it will seed the rest! Some nice water movement would help too. You can just run FOWLR and you wouldn't really need much more light than if it was a fresh water tank! You may even get some nice coralline algae with Kalkwasser and low light! I can see it now! Think about it!

[wedfr]

go with saltwater, much nicer, plus you can do live rock cheaply like the aquarist said.

Either way do yourself a favor and epoxy it now. If you do fresh and then decide to chage it over youll wish you had done it from the beginning

[SaltwaterNovice]

Rbells web site is

http://hettick.netfirms.com/1000gallontank.html

Sorry I forgot to post it before. His concrete tank is a freshwater tank that he built for his redtail cat. He details sealing the tank with a two part epoxy paint.

I would definitely seal the concrete. Concrete is water permeable, i.e., water will travel through it.

I have used thoroughseal on leaking foundations (and it worked great) but never heard of it being used for concrete ponds/tanks. I defer to Leykis on that issue as he has first hand experience. I would just do lots of water changes and check my water parameters, before adding fish, as it probably has some nasty chemicals in it that need to leach out.

I would probably use thoroughseal and epoxy paint. You can never be too safe with that much water. Once the tank is filled it will be almost impossible to repair a leak without breaking down the tank.

You may also want to consider making it a saltwater reef tank. Like Aquarist said you could custom make almost all of your LR. I use crushed oyster shells instead of sand to lighten up my agrocrete. Crushed oyster shells are @ $15.00/50lb bag. You can literally make agrocrete for pennies per pound and you can even use it if you decide to go freshwater.

How about some pictures of that tank?

Best,

Brian

[leykis1o1]

now im my opinion if moisture gets underneath the epoxy resin coating it will start to peal?..since thoroseal is made for the application it binds better im my opinion...you dont see Sea World Epoxy Coating there tanks do you? they are all Thoroseal or similar product

[icebear]

where do you buy this stuff?
can it be bought at home depot?
i did a search on the website and its not listed

[neubauer16]

aquatic ecosystems has it. it is a two part epoxy. it is like 50 bucks a gallon but it works great and it comes int different colors. i've used it a couple times and it turned out great.
jon

www.aquaticeco.com

[marm64]

When I poured my concrete countertops I was looking for something to seal my councrete with and found some good stuff but when I was talking to the salesman he was showing me all kinds of stuff and they had some stuff made specifically for concrete for tanks. I can not remember what the stuff was but it was at a SHerwin-Williams. I would check them out and see what they have to say. It was suppose to be better than epoxy since it was suppose to soak into the concrete and then expand and the then seal.

Good luck

[jjmg]

Here is a project I can love! Salt or fresh, I'd still love it. I don't know anything about building a tank of this size, but there is going to be moisture! Maybe look at some of the indoor pool sites to find out how to handle it?

I'm watching and dreaming, hope it works out.

[saltaholic]

I just tols my wife that I decided that I was going to build a huge concrete tank in the basement of our future house, she took it well. She offered the idea of turning the whole basement into a beach with sand and fake palm trees, etc.. Now who is going to far!!!:D

here is a link to another DIY concrete reef. You got to see this:


Well hmmm nevermind, anyone know what happened too Mr. 4000?

[Bridge Man]

The rebar being referred to earlier is called epoxy coated rebar. It is coated with a green epoxy and should be used anywhere there is the possibility of water infiltration causing damaging rust. LouieM, how thick did you make the concrete walls and did you do any calculations for the amount and size of rebar required? I just want to make sure it is safe.

[Coral Dilema]

Marm64, I think I know what your talking about, its called Dry-Lok and it does an excellent job of sealing concrete and cinderblock. I highly doubt that it is reef safe though. Leykis seems to have the most first hand experience here, If it were mine I would probably take his advice.

[H20ENG]

I used to work at a public aquarium. We had several concrete tanks, including 2 375,000 tanks. They were all coated with epoxy. The smaller (1000 - 2500g) tanks had the acrylic anchor bolted to the front in order to get the most "squish" on the silicone (Dow 795). The anchor bolts were 316 ss, but still countersunk in the acrylic, and coated over with thickened epoxy.
The drawback is that it needs to be on the ground (one tank was raised, but would be WAY too costly for home), and that the front pillars that hold the acrylic stick out from the front of the tank. We solved this by using artificial rockwork.
Thoroseal is good. The last tanks we had done professionally, and they used a polyurethane coating.
I've also used the Herco liquid rubber from Aquatic Ecosystems. Get your respirator out (and your thick wallet!) with great results.
HTH,
Chris