The ones sold in pet shops are mostly junk and I'm surprised they hold anything at all. I have a stand I want to use and have used for smaller tanks but I want to put a whopper on it. It's a solid piece of furniture that was made in the 60's and it's held everything from a big TV to a few smaller fish tanks. At the moment it's holding about 30 gallons worth of tank but I want to more than double that. I felt safe putting my 20 gallon tanks on top of the dressers because the dressers are old and well built and I sat on top of them before risking it. I weigh as much a 20 gallon tank(full) and since they didn't creak or shift at all I felt they were sturdy enough. But how do I tell with something that's going to weigh about a tonne?