Leveling the top of a metal frame

Hi,

This is my first post here, so thanks in advance for any help.

I have been keeping fish for many years and have now embarked on a project to setup my largest tank yet. The tank is a glass tank measuring 7' x 2'6" x 3'.

I have had a metal stand made by a family member. The problem is the metal stand has a slight bow on the top at the front, so with the tank on the stand there is a gap between the tank and stand at each of the front corners, one is about 5mm and the other is 3mm. The tank is currently sat on a 12mm piece of polystyrene foam and there is a 12mm piece of plywood between the foam and tank - I have not put any water in yet as I am concerned about the gap.

What I need to do is make the top level, the bottom is level on the floor.

My current thinking is to box the top in and lay a slab of self levelling concrete so that I get a perfectly level top and then place foam between that and the tank.

Does this sound like a good idea? Has anyone else had this problem? Any better ideas? I'm open to any suggestion.

Thanks,

Rob

Yes its actually at the corners, this is what has me concerned. Here is a picture:



The tank does not have a plastic trim, its a flat glass bottom.

Thanks.

I'm not sure shimming between the tank and the stand is a good idea - everything i have read says you will be simply moving the pressure point.

I have contemplated turning the stand upside down and shimming between the floor and the tank - the stand however was designed to stand one way.

All in the tanks and water are going to weight about 2000kg, so its a lot of weight....

The tank manufacturer said shimming between the tank and stand was not a good idea - that was my first thought.

My understanding is that acrylic flexes more than glass, its a very big piece of glass with lots of water so I'm somewhat concerned. It was hard enough convincing the wife it was a good idea to get it, if it springs a leak she is likely to go crazy