Aquarium stands can be made of many different materials, most common of which is wood. Wood comes in many different varieties, so its important to know what kind of wood your stand is built of. Some stands are made of MDF, aka particle board, and these soak up water like a sponge. They also swell significantly and cause unsightly bumps to appear under the laminate, if present. Solid wood stands are a much better choice, as they are either painted or stained. They resist absorbing water and will last much longer. Chances are, they are much stronger too.