Guy's, I've decided that my 3 week old AGP (18) is too cold , even here in northern Cali. Days are averaging mid 80's with very low humidity and 55/65 at night. I use a cover but the water temp shows only 80/82 on the surface and pretty friggin cold about 1 foot down and further! Not really pleasurable - blue lips and green boogers appear pretty quickly on the kids.... I'm sure I look worse Lol! SO I've ordered a sungrabber heater ( One 4 X 20 ) and it should be here any day. A little reading talks about how flow from the pump is reduced - makes sence, do any of you run a seperate pump and or plumbing? Is it needed? how did you run your extra plumbing? Cut new liner holes or plumb up and over? D'yall think one 4 x 20 is big enough? I'm running a 1hp pump through a 17 sand filer (think thats the size). Really hate being cold, can't fathom you guys in hotter places with a 'water too hot' problem!