Hello, I am working on 2 stands at the same time. Both Of them are for 75gal tanks we got at the dollar per gallon sale at petco. I have completed the skeleton of the stand and am working on the skin cover but I have a question. The tank in some areas is off the top of the stand by about 1/16 of an inch. I did hand plane it a bit and it looks better but it is a 2x4 stand. I tried to pick out the straightest boards at home depot but there are still small dips and bows. Do I need to just suck it up and put a flat top on it or is that gap going to close when I fill the tank?
I tried to add pictures but they are too big.
That gap will likely close... And that is NOT a good thing. That is stress on the glass and will likely eventually lead to a break. Were it me, I would add a 1/2 plywood top, and shim it well where the 2x4 bows. Make sure that plywood is flat where the tank will touch it.
Then for good measure and to insure that other minor imperfections don't stress the tank, put a sheet of 1/4 inch insulation, or closed cell foam (think Yoga Mat) between the tank and the plywood.