Ok lets see I have my new 75 gal tank which has (2) 1 1/2'' bulkheads drilled to the top and the 30 gal sump which has (1) 1 1/2''bulkhead. So my original plan was to have ONE bulkhead as the drain and the other as the return with a eyeball jet. Now my pump of choice will be a mag 18. I came to the realization that may be too much flow on one side of the tank and too little on the other. So I have a new plan. The 2 bulkheads are going to be my drain. My drain will be 2 inch pvc that meets in a T and goes down to a 1 1/2 '' pvc into the sump. I fugure that 1 1/2'' will be enough so there is no backflow. Now as far as my return, I am going to need to convert the mag 18 3/4- either 1 1/4 or 1 1/2 for max flow out of my mag. Now im going to run this 1.25 or 1.5 to the top where its going to split into (2) 1.25 into the tank. One on the right one on the left...so any ideas thoughts comments?