Gap in tank and stand

[Gator2019]

I recently got a 120 gallon corner (pentagon) tank. I built the stand for it and when I got done, the tank didn’t sit flat. There was a gap on the front of the tank between the 2x4 and the tank. I talked to a fellow reefer and he told me to put a thick amount of liquid nails and then put down a piece of plywood. I did that and it was all level. So I let it dry. Ended up letting it dry for 2 weeks and this morning when I go to work on it, the gap is still in the front once I put the tank on. Nothing large, but still a gap. Anything I can do or should I just go with it

 

[Mandelstam]

I would still worry. I don't know how much it matters in reality if the gap is really small but I would try to fix it just for the peace of mind. What I'm going to do for my next stand and what might work for you is to pour out some self leveling concrete on top of the plywood. You can cast that really thin so doesn't have to be much. And it will be completely flat and level once cured. You can use trim as walls while it's curing and seal the gaps with silicone so the "mold" doesn't leak.

 

[Fudsey]

Glass doesn't give and it will probably crack if stressed. I would make sure the tank sits flat before I would fill it.

 

[Gator2019]

I would still worry. I don't know how much it matters in reality if the gap is really small but I would try to fix it just for the peace of mind. What I'm going to do for my next stand and what might work for you is to pour out some self leveling concrete on top of the plywood. You can cast that really thin so doesn't have to be much. And it will be completely flat and level once cured. You can use trim as walls while it's curing and seal the gaps with silicone so the "mold" doesn't leak.

You think I can pour leveling concrete on top of the plywood and it will be smooth enough to put the tank on top of? I have never thought about that before.

 

[Mandelstam]

You think I can pour leveling concrete on top of the plywood and it will be smooth enough to put the tank on top of? I have never thought about that before.

Well they make pretty sturdy floors with that stuff. And maybe I don't use the correct term, English isn't my first language. This is the stuff I'm talking about:

If you use the really runny ones or just mix it extra runny it will self level and be very flat. The only risk I can see is if you don't get the gap where the temporary walls meet the plywood bottom completely waterproof. Then it will leak concrete all over your floor and stand.
I would also put some foam between the concrete and tank as you always should do anyway.

 

[Mandelstam]

https://www.tilecleaning.org/self-leveling-compound.htm

 

[Gator2019]

Well they make pretty sturdy floors with that stuff. And maybe I don't use the correct term, English isn't my first language. This is the stuff I'm talking about:

If you use the really runny ones or just mix it extra runny it will self level and be very flat. The only risk I can see is if you don't get the gap where the temporary walls meet the plywood bottom completely waterproof. Then it will leak concrete all over your floor and stand.
I would also put some foam between the concrete and tank as you always should do anyway.

Foam is what I have wanted to put down, but I have no clue where to find the proper kind. That would for sure fill the rest of the gap

 

[Gator2019]

Well they make pretty sturdy floors with that stuff. And maybe I don't use the correct term, English isn't my first language. This is the stuff I'm talking about:

If you use the really runny ones or just mix it extra runny it will self level and be very flat. The only risk I can see is if you don't get the gap where the temporary walls meet the plywood bottom completely waterproof. Then it will leak concrete all over your floor and stand.
I would also put some foam between the concrete and tank as you always should do anyway.

Foam is what I have wanted to put down, but I have no clue where to find the proper kind. That would for sure fill the rest of the gap

 

[Mandelstam]

Foam is what I have wanted to put down, but I have no clue where to find the proper kind. That would for sure fill the rest of the gap

It would fill the gap but without giving any real support to the tank at that point. Maybe with a thick enough sheet... But the pressure/forces on the tank would still not be 100% equally distributed. The foam will compress less at the area where your gap is. But it will probably be better than having no foam at all.

To me foam is more of a protection against any small debris that could cause pressure points against the glass.

 

[lapin]

Is it possible to put some cabinet shims in the gap? Those are wedge shaped and you might be able to tap them in between the 2x4 and plywood.

 

[Swoody]

Mandelstam has a very good and and easy way of correcting this...simply tack some edge molding of some sort around the perimeter of the top of the stand (to the edge of your plywood....) seal seams with tape and spread a thick enough coat to cover and let it set up...then I would use foam atop of that before placing tank. and I would start with a fresh piece of plywood affixed to the stand....not the piece with the liq. nails on it.

 

[Caliguy1983]

+1 for foam

 

[Fiveo124]

Having a similar issue, 125 gallon 6 foot rimmed tank.

Just put it on the stand all four corners are flat on the stand and all the way around is in contact with the stand except for about 16-22 inches in from the corner on the back of the tank.

In that area I was able to get a piece of thick stock paper in, can barely get a composite shim in there. Should I worry or try to shim it or will this just settle when filled

 

[cracker]

is this gap center front?How about the back. what is the stand actually sitting on? if you can't get more than 2 sheets of thick paper in there I wouldn't worry .
Now Fivo's space is concerning to me. I'd just cut off the shim & lightly work it into the space ,especially if it's right in the center.

 

[Fiveo124]

It’s 20 inches away from the corner so not center. The first picture is with a pice of cardboard packaging that came with some corner braces I used on the stand so about a little thicker than an envelope. The second picture shows how far I can get a shim in there with out forcing it.

 

[cracker]

I assume there's water in the tank? I think I would work the shim "lightly" into the gab & cut off the rest.

 

[Fiveo124]

No water yet, I shimmed it and fixed the problem there but then other spots were uneven so I shimmed there. It’s finally all even there’s only one small spot I can barely get a razor blade it.
It would be nice if there was a magic answer for what tolerance is feesable

 

[Hot2na]

ceiling tile under the whole tank...it will "squish" down in the appropriate spots . you can trim it after the tank is full and paint the edges black

 

[geekengineer]

Its hard to tell how much of a gap is present in this example here, but I was wondering how much (if any) of a gap is acceptable? I maybe have a 1/16 of an inch or less on a couple of the corners on mine.

 

[joethenathan]

No gap is acceptable. Use foam under the tank.