Phosphate levels

[PoolDoc]

Phosphates can contribute to algae growth.

BUT . . . if you're doing everything else correctly, phosphates usually don't matter. Also, most phosphate removers cause problems with cloudiness, and the cloudy mess can be very hard to filter. In the pool shown below, phosphate remover was added to the spa. The entire pool became cloudy -- combined circulation -- and it took 2 weeks, before it was crystal clear again.