Advice: Tank not level/ not fully supported on bottom

[CliftonArbogast]

All, need a little advice. Installed a 360 gallon tank with 3/4 inch glass. put on Styrofoam like the manufacturer required. Tank stand is gnats-a$$ level.

There is a 1.5 Inch portion of the back that is unsupported by the Styrofoam this has caused a 3/8" drop front to back, (the back bottom is 3/8" closer to the stand) Tank is 3 ft. wide, 8 ft. long and 2 ft. tall.

Tank is already in with corals and fish, my dilemma: is this structurally unsound or can they take a little cantilever/overhang. Optically this is not an issue when done with wood trim it will be undetectable. Seams look fine, using the black silicone (unknown type as manufacturer did this.) Let the discussion begin!


Calculations and stress analysis welcome.

[pledosophy]

Glass with styro under it?

1.5" in the back, why no styro there? Pic?

I'd be worried. That's a lot of water on the seam.

[CliftonArbogast]

did not sit right when we were installing it, lots of weight to get er just right, was flat before styro settled a bit

[rfgonzo]

Generally you should not put a glass tank on Styrofoam. Styrofoam should be used under acrylic tanks.

[ca1ore]

Generally you should not put a glass tank on Styrofoam. Styrofoam should be used under acrylic tanks.

That is the conventional wisdom amongst reef central members (in most cases parroting what they have read previously). Seems to me, the best course would be to follow the instructions of the manufacturer. OP states right upfront that he's following said instructions (probably means it's a glasscages tank). That the tank has settled in the back suggests that perhaps the foam used was too compressible, and the extra weight in the back from the rock has caused uneven settling. I doubt, frankly, that a 1 1/2 area would be the cause.

If the tank has settled evenly; in other words, the entire length of the tank is 3/8 out them, while not ideal, is probably something the tank can endure. If the tank is twisting, then that is a very bad thing. I guess either way, I'd feel obliged to fix it; but most certainly if it's twisting.

[gbru316]

Tank with a rim: no styrofoam

tank without a rim: styrofoam

[Eldredge]

If the tank has a rim, the back rim is unsupported and would probably cause settling and be worrisome. You should probably post some pics... Good luck.

[Bilk]

Sure it's not the weight on the floor structure that's causing this?

[CliftonArbogast]

two ft of concrete under tank its not going anywhere, stand still level. Its a euro braced top, all 3/4 inch glass it is a miracles tank.

[Bilk]

two ft of concrete under tank its not going anywhere, stand still level. Its a euro braced top, all 3/4 inch glass it is a miracles tank.
Well I had to ask :) Sometimes we're too close to something to see what's actually happening :)

Edit: 2' of concrete? You said the tanks has a separate stand. What was the purpose of all that concrete? Was the tank planned for the location before the pour?