I built a metal stand out of square 1"square tubing on the top and shelf and 1 1/4 round pipe legs with 1 inch threaded rod attached to feet so that the pipe legs stand on the nut on the rod. I hope that made sense cuz I don't have a picture.
Anyways.... I knew my slab wasn't level because I have um.... water leveled it before

and this way I could adjust for any plumb/level issues. stands perfect now. Might be an idea as I know a few people who after all their original messing around, found that the loaded tank caused a settling of sorts that resulted in an uneasy lean.
my $0.02
Mike