Thanks TP and Brent. Are you saying you can't tie the solar output into the return line to the pool? Surely it's done all the time, right? Isn't that what the T and 3-way valves shown in the 'easy installation' guides show? What am I missing? Hope to have a lot done by tomorrow on my setup. I'll post pics and obviously, data. Output temp, pool temp..etc. Thanks for all the ideas and links.