plywood corner tank height query..

windowlicker

New member
hi i want to build a plywood corner tank 36x36x51 triangle with an overall height of 60" the visible display window will be 40x48 and i intend to use cast acrylic 1" thick with a size of 48x56 which will give me a 4" on all 4 sides to support it.

ive been reading on several sites and checking out other tank builds and a lot of what i read say 30" high is the limit but i have seen a lot of monster tanks that are nearer six foot tall.

what i need to know is that as its a corner tank theres half the amount of water so will this allow me to get the height i desire.

and if it makes any odds the water level would be 2" above the top of the display window so from the bottom of the display window where the acrylic is supported to the water level would be 50".

any advice welcome cheers
 

Rhodophyta

New member
I would suggest your corner tank be a pentagon not a triangle. Sharp corners are traps for dirt and danger spots for fish. This will also bring out the viewing area so it's not blocked by tanks or furniture along the walls near it. You can make it 48" by 48" overall, but with the viewing area as the fifth side of the pentagon, "replacing" one corner of the tank.

Yes, you can make tanks deeper than 48", but there are disadvantages and caveats. You can't reach the bottom to clean without draining out much of the water, or donning a swimsuit. Bulkhead fittings tend to leak in deep parts of plywood tanks. Leaks are more likely in deep tanks. The natural flexing of plywood is exaggerated the deeper the tank. This means much more outside and bottom support for the tank than a typical stand. A sump where water changes can be made so that the water level in the tank does not fluctuate is very desirable, but then you defeat the purpose if you lower the water level for access or cleaning.

A concrete tank makes more sense for such a tall aquarium, but the walls are so thick that you would want a much larger size "footprint" for such a tank.
 

windowlicker

New member
cheers for your thoughts

i have been giving the steel cage idea a lot of thought over the last few days as the main advantage i could see is that there would be less of a recess from the front of the tank to the display glass.

as for the pentagon im afraid im stuck on the triangle idea however i supose i could put something in the corners to make a pentagon shape inside the triangle or is that what you meant?
as you mentioned sump what i had planned was an above tank sump so any drilling if any will be at the top. the main reason for this is that i have 4 children that will find a way into the sump if it was at the bottom and they are the reason i want acrylic as if it was glass i have visions of a toy car or something similar breaking it!

the overall idea is that when the tank and above sump are in place i will be able to clad the front from floor to ceiling to give the affect of an in the wall type tank although i will have to have some kind of access doors to the top of the tank and the sump maybe some sort of flush fit hinges but to be honest i have not thought that far ahead yet.

will the 1" thick cast acrylic definately be up to the job as i dont want to endanger my children?
 

Rhodophyta

New member
Steel rusts and fails near salt spray, so I would steer clear of steel IMO.

You could make it a pentagon inside, but I think it would still have problems in viewing, and accomodating other room furnishings. It would still have sharp corners that I would not trust to hold together. You would have to have a wide border around the viewing area and even if you just filled the tight corner with background, the border would give a porthole effect.

If you went with 36" back sides and 12" ends, a diagonal viewing area would be almost 3 feet across. It would have a narrow border and look more attractive. I have made the side walls 18" which I like better. The way light bends through glass, the sides and the two backs blend into one long expanse and it looks like you are viewing into a much larger tank. Plus you can use a slightly smaller viewing panel whether glass or acrylic while the bending light illusion still makes the view look huge.

To attach the acylic to a plywood tank, you need a gasket. It can't be glued in place with silicone like glass. Not a problem, you just have to plan for a gasket.
 

windowlicker

New member
hi i get your point and am guessing youve done it so now im intrigued do you have a link to your tank so i can get a better understanding of what it looks like?

as for the acrylic what do you mean by gasket it just ive seen several threads where bathroom silicone has been used successfully.
 

chriscobb

New member
Steel rusts and fails near salt spray, so I would steer clear of steel IMO.

Steel left exposed will rust, but the key or trick here is to embed the steel in fully in epoxy and it will not rust.


To attach the acylic to a plywood tank, you need a gasket. It can't be glued in place with silicone like glass. Not a problem, you just have to plan for a gasket.

You again don't need a gasket. Regular silicone will not adhere very well in this situation, and the correct adhesive or sealant that would be needed in this application would be Dow Corning 795........
 
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Rhodophyta

New member
You again don't need a gasket. Regular silicone will not adhere very well in this situation, and the correct adhesive or sealant that would be needed in this application would be Dow Corning 795........

I'm not sure what definition of "need" you mean, but a gasket is dependable and a positive seal. After seeing silicone pop right off acrylic, I would rather have something that does not depend on that combination.

Encasing steel in an epoxy jacket sounds plausible, but one little scratch and it just becomes a cauldron to corrode the metal in.
 
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