Its driving me nuts! My guess is because it was sitting on brand new laminate wood floors that were just installed 4 months ago and nothing was every put over there so it was a little spongey with the foam they roll out underneath. Thats just what I am going to go with. Sump, stand, tank all level before. Now its all level now after filling. But the right overflow will still take on some water after pumps are shut even though the left isnt. Wondering if the teeth are cut out just a little lower than the other side.