When we had our Bathrooms remodeled, I saved the original Kraft-maid Cabinets. The Sides and backs are Particle Board. I have a row of them, with a Pre-formed Laminate Top. I’ve had 45, 30 Gallon, a Refugium / Sump on the Row. Zero deflection/warping on the cabinets. There are different grades of Cabinets. It would be easy to glue and clamp some uprights on the inside corners, if you are worried. I would secure the cabinets to the wall to keep a child from tipping it over. It’s really nice to have a ledge around the Aquarium, to set stuff on while working on it. Also I’d set the Aquarium so the Front Edge is not over the Kick Space.
