Need some opinions here please.

We have some cracks in our fiberglass pool so it's due to be re-lined in the next few weeks.

This would be an ideal time to add an extra inlet so that I can modify the piping to pump some of the water from the pump, up to the stoep roof, through a series of irrigation pipe coils, and back to the new inlet.

As an alternative, I have a slope the other side of the pool ( east facing ) that gets sunlight from sunrise until past noon. I could have an inlet ( top of pool below water level ) and outlet ( bottom of pool ) installed and extend these to a solar heating panel/s sitting on the bank. This would then use natural convection ( thermosiphon ) to take colder water from the bottom of the pool and heat, rise and back into the top of the pool.

The advantage that I see with this is that it would have no effect whatsoever on the pump / filter system, no additional load on the pump, and no effect on the natural circulation in the pool.

The slope is sufficient to position a large panel where the top and bottom would be at the same levels as the new inlet / outlet.

But would it be as effective as the stoep roof coils ?