I'm thinking about adding solar, and have an initial design i'm putting together, so I'm not much ahead of you, but maybe perfect because it is all fresh in my mind.
How it works is many black or dark (typically plastic) tubes absorb heat from the sun while water is running through them. Ideally, fast enough that there is not much of a temperature rise. You want a lot of water with a small temp rise, vs a little water with large temp rise for better efficiency. Your controller [which may just be you manually] turns a valve that diverts the water coming out of your filter (before it goes back to the pool) so now it is running through your Solar panels. This water then is sent back to your pool. Pretty simple. It heats slow, so there is not a big reason for it to cycle on/of/on rapidly like your home heating system, so a manual valve is not unreasonable.
A few things i've learned so far about solar:
1) Rule of thumb is ~same square footage as your pool. But if you have ideal conditions, low wind, high flow rate (efficiency), and the perfect angle to the sun in a low-cloud area, less will work well. If you have non optimal [i.e., NOT south facing], or some shading, or lots of wind, or other negatives, you may want to go greater than 1:1 area. Again, rule of thumb. There is a guy that has a good calculator if you are doing it yourself [H2otsun.com], or if you want to get a feel for how much area you need given your desired temperature rise.
2) 80 degrees seems to be the standard temp for comparison.
3) since you lose plenty of heat at night, as poodv says, you will need more solar to overcome, or a cover. Said another way, if you can only get 50% of your pool surface area in solar, but have a pool cover that insulates well, maybe that is as good as a 75% solar system without a cover.
4) It appears it is not like a heater that cycles on/off with a +/-1 degree set point. Rather, a valve turns on, you pump the water up into the system, and warming takes place over hours. Once your controller reaches temp, the valve turns off, and much of the water in the system drains out due to a vacuum breaker at the highest point. I struggle with this one because you are always pushing the water up and you never get the advantage of the suction on the way back down. having said that, my 24' rise seems like it will only take an additional 10 psi, so it is not the end of the world. I'm looking into an approach that opens an electric valve once the system is shut down vs a vacuum breaker to enable the benefit of the falling water, but this is just me, and there probably is a good reason not to do this.
5) It looks like in your area there are oppotunities for freezing, so make sure you system does completely drain. Setting it at a slight angle, or orienting the system from top to bottom with a vacuum breaker should do this.
6) if you are doing it yourself, post the design here. You have to make sure you have a balanced pressure differential across the system. Basically, if you are feeding your arrays from the bottom left, you want the returns to be from the top right, so everything has an equal pressure differential.
7)
