This is the sump return. I used 1/2 inch P traps in order to avoid using 45 or 90 degree elbows which would reduce flow. I honestly dont know how much more efficient these are....but I'm guessing they work better this way since there are gentle curves in the plumbing as opposed to sharper angles. I will do a test later to calculate how much water this is moving, (Mag 7 with about 4 feet of head...According to Custom Aquatic's catalog, it should be in the vicinity of 460 GPH if I remember correctly). I will also use the RC flow calculator and estimate what the flow would be using 45 degree elbows and also with 90 degree elbows just to compare.
These Rigid P traps were available at Lowes, and were available in 1/2 and 3/4 inch sizes. I was not able to find them at Home Depot, (actually got blank looks when I asked about them).
Nick