If you don't have natural gas available, for gas a gas fired heater, propane is the only option.

Raypak and Rheem are the same unit with different skins and a slightly different top. The insides are the same.

The Sta-Rite is a Pentair, also with a different skin. Better unit than the Raypak. Longer lasting and more reliable in the long run. Expect to pay more because it's better engineered. You'll get what you pay for.

That is a large pool. You will need either a solar cover or a liquid cover to contain the evaporation. That is the #1 heat loss cause because heat rises.

Scott

Scott, thanks. Always appreciate your input. Out here in the countryside, propane is my only option.
What do you mean by "a liquid cover"?

An fine example of a liquid pool cover is the Heat Saver line of products. Often found at local pool stores, the come in a disposable liquid filled clown fish looking dispenser or a peristaltic pump activated bulk dispenser.

They release a small amount of solution that rises to the surface of a calm pool and forms a very thin barrier that stops evaporation, the #1 cause of lost heat. It doesn't seem to leave any residues when the surface is disturbed however in windy and or rainy conditions, the film is broken up. It reforms when the wind and rain die down.

The main benefit is that propane is pretty costly. The less you have to heat the water, the less propane you will use. They aren't quite as effective as a solar cover but are a heck of a lot easier to use and are still cost effective.

Scott

Here is a link that might be useful: Heat Saver and Eco Saver. They don't sell direct to homeowners.

Getting ready to purchase the Raypak 406A, pool company suggested the Raypak 466A, which uses cupro-nickel, because I have a saltwater pool. Any thoughts? This company believes that Raypak has made improvements and is slightly more reliable than the Sta-Rite. Again, any thoughts? Thanks.

I've had a Pentair and I now have the Raypak 406. Much prefer the Raypak.

I almost did C-N, but didn't, I don't have a salt pool. I did go with the Raypak ASME unit, which has a thicker walls on the copper heat exchanger than the non-ASME unit.