You'll be amazed at how much even two panels will help. The figuring is based on the surface area of the pool, which really makes no sense. After all, you have to heat a volume of water, not an area. All 20,000 gallon pools (for example) should require aproximately the same amount of solar panels. I/Gs may get away with less as the surrounding ground becomes a heat reservoir.
Of course, the more surface area you have, the more heat you lose to convection. But with a good solar cover, you reverse that: The more surface you have the greater the greenhouse effect to heat your pool.
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