The panels take up a lot of space, and create a good deal of backpressure so your pump will not circulate as much water as it is supposed to. Further, an IG pool is going to require a lot more surface area. You really need about the same surface area in panels as your pool has, if not more. Further, they won't do much for you in the early spring and late fall when you really need the most heating. Heck, my heating needs during July and August in NJ are almost zero anyway with a cover on the pool at night.

What I have is an electric heatpump which extracts "free" heat out of the air and dumps it in the pool. I have PV solar panels on my roof which generate electricity. My 10kw system generates about 12,000 kwh per year. Here in NJ there is a great rebate program on solar electric systems where the state pays about 60% of the system cost. When I installed mine they were paying 70%. I figure the system will pay for itself in just under 4 years, after that its a cash cow.

I have time-of-day metering for my electric, so we pay higher rates during peak periods and low rates at off peak time. I run the heat pump at nights and on weekends when power is cheap. The PV system spins my meter backward during the day when power rates are high. This is probably the most efficient overall system to have.