I have a single hang on overflow box. Amiracle brand I think. It has a single U tube and a Single Drain. I want to add another drain (or bigger one) and second U tube to increase the flow the box can handle. Will I have to widen the teeth on the inside box? Can I just cut away all the teeth and use a screen of some kind? The tank is small so adding a whole second box or even double box is out for me. Any input/insight would be great.