300 gal tank with pvc bottom bowing on bottom

[whitelightning77]

Well, I've been having a hard time leveling this tank on the stand. You would think it would be the tank plywood top to be the issue but I did my best to make the top as level as possible. The left side of the tank sits flush but the right side sits almost 1/2" off the stand.

I raised the tank off the stand and noticed some bowing of the pvc bottom in the middle. So I placed a rubber mat under but that didn't help much at all. The tank still was raised on the right. Last light I raised it even hight and placed the level under. The stand is def pretty level and the pvc bottom is pretty bowed.

Anyone have any experience with this? Am I om just leveling the stand and filling with water? Maybe the weight of the water will flatten out the bottom? I've read threads where tanks with pvc bottoms bow when not filled and why they need to be placed on stands with plywood top

s.

 

[whitelightning77]

I asked this in my build thread but not getting much action there so I figured I'd ask in a separate thread.

 

[dadnjesse]

It's hard to tell but that last picture the stand looks unlevel to me. Did you put a level at the bottom of the tank? If it's a 6 foot tank you should use a 6 foot level. Maybe use a string across the bottom.

 

[workhz]

What’s that hollow looking section in the plywood? Are you sure your stand is level and flat?

 

[whitelightning77]

It's hard to tell but that last picture the stand looks unlevel to me. Did you put a level at the bottom of the tank? If it's a 6 foot tank you should use a 6 foot level. Maybe use a string across the bottom.

Yes its a little deceptive. The stand is pretty much straight on the plywood top. We're talking maybe 1/16" -1/8" discrepancy from one end of the stand to the other (84"). Believe me, I too thought maybe the stand was unlevel but after I raised the tank for a second time and placed it on the 2x4 blocks so I can get my 6' level underneath, when placing the level up against the bottom of the tank it is definitely bowed downward.

 

[whitelightning77]

You can see in the photos how the level sits flush against the top of the stand but right above it you can see how the level hits the middle of the tank, but out towards the sides there is about 1/2" gap between the top of the level and the bottom of the tank.

 

[pandaparties]

You can see in the photos how the level sits flush against the top of the stand but right above it you can see how the level hits the middle of the tank, but out towards the sides there is about 1/2" gap between the top of the level and the bottom of the tank.

If the stand isnt level then sticking the level on the stand and lifting the tank like you are isn't going to show anything useful. Either way if it's truly unlevel on the tank (I'd flip it upsidedown and check with a digital level, because I'm still skeptical) then I'd contact the MFG. I've never heard of empty tanks bowing. If they won't replace it you could gamble on throwing Styrofoam underneath and hoping that it can conform. If it's too off it's still not going to work though

 

[workhz]

The wood and the bricks all exactly the same highly?

I’d still take the tank down and put a 6’ level across everything. It probably doesn’t even need to be a level, just something you know is straight.

 

[whitelightning77]

If the stand isnt level then sticking the level on the stand and lifting the tank like you are isn't going to show anything useful. Either way if it's truly unlevel on the tank (I'd flip it upsidedown and check with a digital level, because I'm still skeptical) then I'd contact the MFG. I've never heard of empty tanks bowing. If they won't replace it you could gamble on throwing Styrofoam underneath and hoping that it can conform. If it's too off it's still not going to work though

I'm not concerned with the stand being level right now. I can shim the stand to make it level. What I'm asking about is the bottom of the tank which is PVC bowing downward. You easily see that the level sitting on the stand sits flat against the plywood, there is almost no light coming through under the level, while above the level you can see the bottom of the tank touching the middle of the level and the left and right side of the tank sits about 1/2" above the level. Leading you to see that the middle of the tank is bowing downward. So when you sit the tank on the stand, even if its level, the corners or sides of the tank to sit on the plywood properly because the middle of the pvc bottom doesn't let the sides come down. Its pvc though and it flexes, so if I push down on the sides of the tank it pushes the pvc up. So I'm thinking if I fill It with water the weight of the water will let it level out. The guy that I got it from had it running for about 3 or 4 years and had no issues with it.

 

[whitelightning77]

The wood and the bricks all exactly the same highly?

I’d still take the tank down and put a 6’ level across everything. It probably doesn’t even need to be a level, just something you know is straight.

There is a 6' level on the stand right now, under the tank. And thats exactly what I'm trying to say. The stand top is straight. The bottom of the tank, which is pvc, looks like its not.