Urgent problem with 210 gallon tank

[DrHank]

Earlier this summer I purchased a used 210 gallon tank (96"X24"X21"high) . It was configured as a breeder tank with 3 internal baffles and a 2" bulkhead in the bottom for the drain. I removed the baffles and installed 3 3"X1/2" thick cross supports at the top with GE Silicone I.

The tank has been in operation for about a month now and when I was doing a water change this afternoon I noticed that 2 of the 3 braces had pulled loose (probably due to the internal pressure on the tank. I'm concerned for obvious reasons. Can anyone tell me if I should worry about the lack of top cross braces. I know that they are making rimless tanks now but do they need cross bracing? Does my tank need cross bracing?

Should I start looking for another tank?

 

[Reeferdude]

I wouldn't think those supports should have come loose unless there was too large of a gap between the two surfaces. Did you thoroughly clean the surfaces prior to applying the Silicone, and did you clamp the braces completely squeezing out all but the thin layer left behind, and were the supports glass, and did you put the supports on top or inside the tank? Maybe go with wider support, say 6 inches each...

 

[mmkeeper]

Take a long straight edge and place length wise along the bottom middle and top of the glass and see if it is bowing out.

 

[MC Lighting]

something expanded to pop them loose I agree with the above post check to see if it is bowing and get it fixed ASAP I would not trust it without the braces as the tank was not designed to be without it...

 

[DrHank]

There wasn't much of a gap between the two surfaces. I did thoroughly clean the surfaces prior to applying the Silicone, and did not clamp the braces completely squeezing out all but the thin layer left behind. The supports were glass, and they were put inside the tank.

Even if I could fix the tank so that it doesn't bow, I don't imagine that I could do it without breaking the tank down. Any other thoughts or advice?

 

[mmkeeper]

Acrylic or glass?. If glass when you used the silicone was their a flat surface under the brace?

 

[mmkeeper]

Here is how I replaced the cross member on my tank. I got a piece of clear acrylic(so the light would pass thru) drilled each end of the acrylic and the ledge of the tank I was gluing it to. I glued and clamped using weldon 16 and glue acrylic dowels cut to lenght in the holes that I drilled. So as the pressure wanted to spread the sides of the tank the dowels would keep it in place.

 

[Reeferdude]

There wasn't much of a gap between the two surfaces. I did thoroughly clean the surfaces prior to applying the Silicone, and did not clamp the braces completely squeezing out all but the thin layer left behind. The supports were glass, and they were put inside the tank.

Even if I could fix the tank so that it doesn't bow, I don't imagine that I could do it without breaking the tank down. Any other thoughts or advice?

You don't need to tear it down. May need to lower the water level though. There cannot be any gap between the surfaces. Remove the braces, use clamps and a couple 2x4s to support the tank front and back from bowing further while you remove them. Clean the surfaces to be joined 100% of old Silicone and debris. Silicone both surfaces of each brace and spot on tank. Clamp the braces so all the Silicone squeezes out leaving nothing but the remaining silicone. The trick. The braces must be precisely cut to the same length as the end walls so as not to bow inward, outward or leave a gap at any joint. This works. I've had to do it. As long as the tank and braces are glass it'll work.

 

[drgreen]

If you can put a 3” by 2” anchor under each edge that touches the tank this always helps me to form a good strong bond to each surface and spreads the stress to a larger area. |==-------==| .hope that makes sense

 

[DrHank]

Thanks folks I'll give it another try. Guess I just didn't do it right the first time.

 

[danno14]

I would consider acrylic glue instead of silicone.... weldon brand is pretty commonly used. Silicone is not designed to prevent shear movement, which is what you are experiencing. Best of luck, D