We have two 40 gallon breeders that I want to convert to fish tanks and I need some help with how to do it. One of the tanks is a standard 40 breeder with no center brace and a metal screen lid. The other tank has kind of a meshy screen lid that slides into the top of the tank from the front (the kind made for reptiles). I don't know what kind of a cover to use, I have only found one and it says it's two pieces and needs a center brace. Any ideas on what to do?