Floc is a pool additive used to gather together loose debris in a cloudy pool and drive it down to the pool bottom, according to Swim University. Once on the bottom, the cloudy water is vacuumed away, leaving the remaining pool water clear.
The gathered debris from the flocculant is removed using a manual pool vacuum. The vacuum must be on waste mode, as the gathered chunks of debris are too large to go through a pool filter. Using the floc and vacuum method can typically clear a cloudy pool in about 24 hours. The process also removes some water from the pool.