Questions about stand for 600+ gallon tank

[HarlequinTuskReef]

I recently purchased a ~ 600+ gallon tank. Actual tank dimensions are 10 ft x 37.5" wide x 36.5" tall. The tank weighs 1150 lbs empty so it is extremely difficult to move without a group of people. The stand was rushed as the tank shipped 1.5 weeks earlier then it was supposed to be so I was not ready and had to pull 3 overnighters to prepare the final tank location. The stand is 2x6 construction with 2 sheets of .75" maple plywood overlapped on top and 1 sheet on the bottom of the stand. Then a sheet of 1" Styrofoam insulation (bought from home depot) was placed between the stand and the tank as per manufacturers recommendation.
While filling the tank I was checking the Styrofoam and noticed that in one small section the Styrofoam is not compressed. I used shims to check the amount and noticed that the gap before Styrofoam compresses is ~0.100 inch with the tank 65-75% filled see attached pic. I went around the entire tank and checked the Styrofoam and I can not stick a shim in between the stand and the Styrofoam anywhere else. Also note that the gap is located where two sheets of Styrofoam were spliced together (8ft sheet and 2 ft sheet). So I'm wondering if its from 2 different thickness sheets even though the tank is resting on this sheet fine everywhere else.
I know the best thing to do would be to drain the tank and check the stand but this would be a massive amount of work so I'm looking for any ideas on how to do this without going that route. One idea I had is to use a car jack and lift the tank in that spot until the Styrofoam is in contact with the glass and then add a support there cut to size. as long as the tank is supported by the Styrofoam i don't think there should be any issues. Thoughts?

 

[reef lover]

Unless the stand is unsquare/level...i cant see that big of a tank not touching...i would address the stand before filling so it nots 600 gals of water on the floor...

 

[AlexG]

I would recommend draining the tank for safety until you know what the issue is. This is an odd spot for the Styrofoam to not be compressing. Was the level of the stand checked before tank was put on the stand? Was the tank level checked before it was test filled? Has the tank level changed at all since it has been filled? Do you have any pictures of the underside of the stand so I can see the bracing construction? Is the Styrofoam on the other side of that corner also showing a lack of compression when measurements are compared to the foam thickness on the other corners that are compressed? A tank drain will allow you to see how the compression changes on the Styrofoam/stand. Its possible that as the tank is being filled that the stand is warping causing the stand to twist slightly creating a lack of contact in this corner of the tank. If this is a stand issue then leveling the stand itself with shims might clear your issue. I think that seeing the bracing in place n the stand might also help to determine if this type of issue can happen.