Well, it's good the stand was sold with the tank so there won't be any, "You didn't place the tank on an appropriate stand" nonsense. I don't know what to say about the sticker but you do have a receipt that states you purchased the tank from a retailer. Ask the retailer for some help on this maybe?
It's been a very long time since I rented but if I'm not mistaken the building will carry insurance to cover the costs of repairing flood damage. Of course, the owner will try to recoup his loss by finding you liable for repairs but then that should be deferred to All Glass. What a mess. I'm off to google some info for you.