A lot of a pool's heat is lost through the surface at night. A solar cover will trap in much of the heat that would have otherwise been lost. For example, with my cover on I will likely lose 3 degrees on a cool night versus 5 or 6 without the cover. So a solar blanket is a must to keep your heat in. As for generating heat, I think some people think it helps a bit, but likely only for the top few inches of water. I don't know all the science on it or anything, but I believe the solar cover is a great help in its heat retention, but not so awesome for doing the heating. The biggest cost for me to get my gas heater was the install - that is, getting the gas line to the spot I needed it. Of course that was one-time cost so over time it doesn't hurt as much. If I didn't have a gas heater, I wouldn't have a pool in my climate, which I believe to be a bit like yours. Oh -- the solar rings will be the same story as the solar blanket.