Solar heater for pool on shabbat

I have an above ground pool, and I’ve built a solar heater for it. The the heater is a coiled plastic pipe in a box with a clear plastic covering it. I have an electronic pump on a timer, that pumps the pool water through the heater and back into the pool. If the timer is set before Shabbat, can I have it on on Shabbat and swim in it?