Hi - my 75-gallon tank and stand are capable of wobbling if you just jump on the floor near it. I can get the water slushing back and forth pretty well by jumping 4-5 times near it. This is odd to me. I have young kids and it worries me. It sits on a carpeted floor with a cement subfloor. I've leveled it off with shims. When it was on the floor flush it was not level, and so I had to shim to get level. I can't determine the cause or location of the wobble. Meaning, I don't see a certain section of the stand moving back and forth. It seems to sort of move as one with the wobble. So could this just be a product of a cement floor? That ties in all the motion from the whole slab? We're in a condo on the 2nd floor. And I have to have it level - right? So nothing I can do there (removing shims). Perplexed as to my next step to secure this tank and eliminate wobble. I was thinking of doing a big water change and perhaps, once it's lighter in weight, removing the shims and either letting it rest flush on the carpet again to test it, or just start over with the leveling process and hope to get it done without the wobble. Thoughts? Thanks.