Great idea, that was actually gonna be one of my next questions. What size would you use for the loop? I'm working on the plumbing diagram now so I'm gonna have tons of questions. I hope this is where I should be posting as opposed to starting a new thread for each question. How many reutrns do people normally go with? 15,000 gallon pool, 520 sq. ft. of surface area plus 50 sq. ft. for the spa. Should I use 2.5-3" or will 2-2.5" be sufficient for the runs? The set is currently all 2" plumbing with 2-2 1/2†valves and I'm not going to redo it all. Can I run one suction line, from one main drain, Tee to the other, into the skimmer then one run to the pad or should I have two suction lines to the pad? Do both main drains have a hydrostatic valve or is only one needed? No need for a hydrostatic valve in the spa right? I really appreciate your help and once I become educated, promise to pass it along.