I just built a new stand. It is for a 90 gallon tank.
The frame was built out of 2x4's and framed with plywood and trim.
After I built the frame, I put the stand on it and there was no rocking - it was completely fine!
Now I have put all the plywood on, put the trim on and finished it. I moved the stand out of the garage and put the tank on it and it is ROCKING!
The stand does not rock, but the tank on the stand rocks. It isn't much at all, but I want to know how paranoid I should be. I believe the amount of travel is equivalent to about a 16th of an inch.
I filled it halfway with water last night and the rocking stopped, I then emptied the tank and it was rocking again. I can put a shim underneath the corner, but I'd like to know if that is OK to do.
Finally, there are a few spots where I can see a sliver of light between the bottom of the tank and the 2x4. Do you think that is an issue?
I would like to point out that I realize 2x4s are not perfectly flat like dimensioned lumber is. I just want to know if others who have built their stands have experienced the same and if I am just being too paranoid?!