65 gallon salt and 55 gallon fresh in a 2nd floor apt. No worries so far. Both are on load bearing walls, the 65 being next to an outside wall on a corner. Combined weight of these tanks is likely upwards of 1200 pounds. If your home has joists in the floor instead of a slab, you might see if there is a way you can find out which way the joists run and setup the tank so the joists run oerpendicular to the length of the tank, so more than one or two joists bear weight. Another good idea for all stands in my opinion is to cut a piece of 3/4 inch plywood about a 1/2 larger than the base dimensions of the stand and put the stand on that to help spread weight even more.