Help with gap under tank

[RemainVayne]

I built a DIY stand out of 2x6s for my acrylic aquarium. It's square and perfectly level and has a sheet of .75" sanded pine plywood resting on top.

After placing the tank on the stand, there was quite a gap in the middle of the stand between the tank and plywood, which runs from the center and for a bit towards both sides. I shimmed between the plywood and stand to get the tank touching the plywood in all spots. Are the pics below the right way to shim? I'm worried about my brand new acrylic tank cracking and a ton of water ending up on my basement floor...

 

[Dloks]

I would redo it especially since you have an acrylic tank

 

[RemainVayne]

I would redo it especially since you have an acrylic tank

Redo what? Not sure what I can fix with the stand as it was spot-on before placing the tank on it.

Do I need to have shims in all of the gaps pictured between the plywood and stand?

 

[Dloks]

I’ve had bad experience with acrylic tanks bowing due to bad stand support. If that plywood bows so will the tank, imagine all that water busted from the bottom seam

 

[RemainVayne]

Guess I don't know what to fix then since the 2x6 stand was true and level prior to the tank being placed on it.

I might fill in all the gaps with shims to support the seam?

 

[monkeybike]

Unscrew, shim between braces to lift the horizontal beam. I had to do that with the middle support on my stand to bring the plywood tight to the bottom rim in the middle of my tank.

 

[RemainVayne]

Unscrew, shim between braces to lift the horizontal beam. I had to do that with the middle support on my stand to bring the plywood tight to the bottom rim in the middle of my tank.

View attachment 1347633

If I go this route, can I unscrew those vertical braces and shim with the tank still on the stand? Otherwise I wouldn't know when the plywood would be good to go?

 

[RemainVayne]

I think I may know what the problem is.

Looks like my top horizontal support pieces, the ones which connect my 2x6s together, aren't completely flush with the top of the tank. If they are moved up a touch, they'll better support (and push up) the plywood, which would then connect with the tank bottom.



I think...

 

[RemainVayne]

Crap, or maybe the bottom of the tank is slightly bowed. If that's the case, what can I even do?

 

[monkeybike]

If I go this route, can I unscrew those vertical braces and shim with the tank still on the stand? Otherwise I wouldn't know when the plywood would be good to go?

That's what I did, albeit with a glass tank