How level does a tank have to be ? I just finished the plumbing on my tank - just waiting for the solvent to glue - and want to water test it tomorrow but the tank and stand are not perfectly level. On the bubble level, the bubble is within the marks but slightly more to one mark. This goes for both sides ( front to back ) of the tank but its not exactly to the same degree on each side. I tried moving the stand a little in each direction ( its a basement floor so concrete foundation, no carpet or anything ) without success. I bought a pack of shims but I think they might be too much plus I dont know how smart it is to have one shim under all that weight. The tank is a 65 gallon AGA and the stand is pretty solid.