As long as the as the top of the stand is smooth and level (which it should be) there is no need for a plywood top. The tank is only supported by the edges.
Unless you have a frame less tank, then you may want to cover it and use a sheet of styrofoam under the tank.
Your stand doesn't need any more wood, it's VERY strong.
Much larger tanks are held up with a lot less on store bought stands.
Unless you have a frame less tank, then you may want to cover it and use a sheet of styrofoam under the tank.
Your stand doesn't need any more wood, it's VERY strong.

Much larger tanks are held up with a lot less on store bought stands.
