New 55 gallon on carpet--safe?

[tankenvy]

I just picked up a friend's 55 gallon tank and cast iron stand. Sanded and painted the stand, cleaned the tank, both look great. But I set up the stand in my basement, which has a relatively thin carpet. My question: do I need to place anything on the carpet, directly under the legs of the stand, to stabilize the setup? How about the top of the stand--it has a bit of rust and when I sanded, there's some uneven spots, where the metal surface is a bit lower due to sanding. Should I use shims and/or plywood to make a level surface or can the tank go on top as is?

I realize this setup, with gravel and wood and water, is gonna by close to 1,000 lbs, so I want to make sure the setup is as safe as possible. My wife's mad enough as it is, when she saw this thing come into the house:eek:

[pjrichar]

use the prefinish shelving board that lowes or homedepot sells its the white finished maybe 3/4 inch thick they will cut to size for free.. i have all mine on that .. looks nice and make a little bigger then there are little shelves on each end for fish food etc etc..