Slightly twisted steel stand

[David R]

I'm setting up my 160g (150lx70wx60h) in the garage on the bare concrete floor. I had a stand made from 30mm square steel, with eight legs (see pic). I'm in a bit of a predicament; the stand has a slight twist, so when the front left leg is on the ground the back right is about 4-5mm off the ground. Two people (around 60kg each) standing on opposite corners is enough to flex the stand so it is level. Obviously the weight of the full tank will be far greater than this, so it will level itself out, but I'm worried about the force stressing the tank, and possibly cracking it. The tank is made from 12mm glass and and has bracing along the front and back, top and bottom.

The other thing is that the ends of the legs and the concrete is not perfectly parallel, so I was thinking of putting a piece of 3x3x1" timber under each leg to act like polystyrene under a tank and even up the weight. Is this a good idea, or is the wood likely to crush and split with the weight of the tank on it?
I think I may just be being paranoid, if it was going on a floor with carpet you probably wouldn't even notice little things like this!

Here's the stand and tank:

 

[kumdoalan]

Have you had a test run of putting the tank on top of the stand and filling with water yet?

To tell the truth I also have a metal stand that the one time I saw it without the tank on top I noticed it was also a bit warped.

I think it must twist a bit from the heat when the guy was welding it.
I didnt do anything to fix it and thats been 20 years now.

I had another tank that the floor underneath was not level so I shimmed it and that fixed that problem.

I wish you luck and hope someone who knows what to do will answer soon.

BUMP

 

[David R]

Have you had a test run of putting the tank on top of the stand and filling with water yet?

Not yet, just finished painting the ply to go on top of the stand, so I can try that tomorrow if I can get someone to help me lift the tank!

To tell the truth I also have a metal stand that the one time I saw it without the tank on top I noticed it was also a bit warped.
I think it must twist a bit from the heat when the guy was welding it.
I didnt do anything to fix it and thats been 20 years now.

Yeah thats what I'm thinking too, must be nearly impossible to weld it 100% dead square. I'm guessing it should be fine, if it will level out with only 60kg on it, just want to be 110% sure.

I had another tank that the floor underneath was not level so I shimmed it and that fixed that problem.

I'm planning on shimming it if needed, I've got some pieces of 1mm, 2mm and 3mm steel I can use, I'm not sure just how dead accurate it needs to be. As I said, it would be impossible to do on a floor with carpet as you'd never notice the small gaps, so maybe I'm worrying too much?

Oh, and another thing, is 10mm polystyrene thick enough (on top of 15mm ply on top of the stand)? As I understand, anything thicker isn't necessary because they poly is only good for absorbing small defects, certainly nothing anywhere near as big as 10mm.

Cheers!