Can anyone give me a reason not to put a fish tank on top of the stand I’ve made, which has pillars made from 9mm ply and the top and bottom from 18mm pine board? Will it bow if I put the fish tank on top? The tank is running the full length and weighs 125 kilograms when full. – Jordan Jon Matthews
Chris Marshall: It’s difficult to know for sure if the stand will support your aquarium without seeing a picture of your design. At 125 kilograms (275 lbs.), the stand will definitely be carrying a pretty hefty load of water and glass. I would add cross supports or stretchers under the top board, and tie those into the pillars. Then, I’d install additional cross supports further down the pillars to help the stand resist racking. A back panel, fastened along the length of the pillars, would add significant stiffness, too. This is a base you don’t want to have fail on you, for any number of reasons (that include flooding!), so I’d err on the side of overbuilding it.
Tim Inman: Well, I’m an old bald-headed English guy, so let’s get these numbers sorted into something I can understand before we go any further. Nine mm is just under 3/8-inches. Eighteen mm is well short of 3/4-in. material. One hundred twenty five kilograms comes out at a little over 275 pounds. So, we’re looking at basically 3/4-in. pine boards supported on 3/8-in. columns holding up 275 pounds of dead weight. My best guess is that should hold. If the columns are long, then it may be a little tippy, and a fish tank that is tippy is not a good thing. Any vibration in the room from bad flooring or trucks going by too fast? All this factors in. I’m a finisher, not a structural engineer, but I would say you’re good to go. Buy insurance for the people in the basement though.