Solar heat in parallel w/ gas?

[wetviking]

Thanks Carl, I think I'll experiement a bit once the gas heater is set up.

[Poconos]

Any kind of multiple heating configuration you always want the heaters in parallel, not series. You get maximum heat transfer from the heat source, whether it be gas or sun, to water when the temperature differential is highest. Thus you don't want to run pre-heated water into a gas heater or the other way. The only thing you'll have to watch is to maintain enough flow through the gas heater so it doesn't trip off for low flow.
Al

[CarlD]

Any kind of multiple heating configuration you always want the heaters in parallel, not series. You get maximum heat transfer from the heat source, whether it be gas or sun, to water when the temperature differential is highest. Thus you don't want to run pre-heated water into a gas heater or the other way. The only thing you'll have to watch is to maintain enough flow through the gas heater so it doesn't trip off for low flow.
Al

I TRIED to say that but Al put it so much more clearly.

To this I'll add: It's not temperature that heats your pool, it's calories or BTUs (metric vs English). Every BTU warms your water. I split my own system in two to increase flow over temperature. If it was practical, I'd split it again into 4 units. Plus, I get to turn on the units in the sun and turn off shaded units.