I purchased at 240g (8x2x2) reef ready tank with four 1 inch bulkheads. The previous owner had it set up with two returns and two used to feed the sump. I plan to keep them set up the same. I read that 1 inch bulkheads flow around 600 gph each. The previous owner did not use any kind of overflow pipes he let the water fall into the overflow chamber and drain through the holes. I am going to put two durso standpipes. What I'm unsure of is whether or not I should run one big pump or would two Eheim 1262s work each feeding a return line. They should flow around 600 gph with head loss. TIA