My question is why would the out going line on the holding tank be reduced to 1.25 and then tee and go back up to 1.5? Incoming is 1.5 from the head. Was it a clearance problem which could be fixed by building up the surface the tank sits on? Fisheries Supply had no Idea but thought it should be changed back to 1.5? Any ideas why? Also got a new Head (PHII) from online, I highly recommend. Price was better that anyone I found on line or in store. $215 plus shipping. The pump unit which had a crack and was orginal from 79 needed to be replaced and it was $185. Also am replacing all the hoses with Sealand odor safe. Pricey but am hoping it is worth it. It's real hard to work with.