i have a 75 gal glass tank drilled for 1 1/2" over flow and 1" return. The over flow is 3 1/4" from edge of tank and 1" from bottom of top bracket. I am using a 2" pvc elbow in tank. would like something different like an internal overflow box. going to sump. as far as my return i need to know how to get the best water. for circulation. for detritus removal and dead spots. any suggestions, pictures and places to get plumbing internal overflow box from would be helpful.