Pool flocculant, also known as pool floc, clumps together the tiny particles in your pool that cause cloudy water. Once those particles have coagulated, the larger clumps sink to the bottom of your swimming pool where they're vacuumed out

Can you swim after adding flock?
Swim only after the floc has settled to the bottom of the pool and been vacuumed to waste. Depending on how much you have added and the size of your pool, it is generally safe to wait about 4 hours after adding liquid chlorine or until levels reach 5 ppm or lower.