I have a 125 gal glass tank which is going to be saltwater. I plan to make a dual overflow out of pvc pipe. One inch pipe to a 1.25 inch center pipe to the sump. My question is this. Can i use 1 inch pipe for a return to the tank? Or could i use two 3/4 inch pipes for the overflows? And 1 inch return? I would like to achieve around 600 gph turn over.