Pool Care 101: All You Need to Know About Pool Flocculants

There is no more ominous sight than staring at a cloudy, murky pool. And there is no more ominous feeling than knowing that you can’t enjoy the water because something has turned it into a dark mishmash of unknown particles. 

If you have been in this situation as a pool owner, know that there is always good news and bad news. The bad news is, you need to roll your sleeves up because clearing the pool water involves plenty of hard work. But the good news is, you can buy something at your local hardware store that can assist you with the task. 

What is it? It’s a pool flocculant.

What are Pool Flocculants?

Pool flocculants, or pool floc, are substances in powdered form that lumps together the particles that cause cloudy. Cloudy pool water may have algae, bacteria, viruses, and other substances in it. Pool floc coagulates them, bundles them up, and sinks them to the bottom of the pool. From there, the gunk can be vacuumed manually or suctioned toward the filter.

Difference Between Pool Floc and Pool Clarifier

You may have heard about a substance called a “pool clarifier.” By definition, a pool clarifier and a pool floc are both substances that help clear the pool water up, but with some major differences. What are these?

  • Clarifiers also clump particles together, but these particles are discarded through the filter. Pool flocs, on the other hand, cause the lumped particles to sink. Hence, using floc is faster, taking only 24 hours, while clarifiers may need several days to work.
  • Pool water clarifiers should only be used if you have a filter cartridge. If your pool uses sand or DE filters, then you have no choice but to use a pool flocculant. This is because sand and DE filters could be bypassed using one of the valve selectors while cartridge filters could not.
  • You will definitely lose a lot of water volume when using pool flocculants, but not so with a clarifier.

When to Use Pool Flocculants or Clarifiers

There are three main factors when deciding what to use between a pool floc or a pool clarifier: the filter type, the degree of cloudiness, and when the pool must be used.

Generally, if the pool is just slightly cloudy (which means you can still see your feet from 36 inches down), then a pool clarifier will suffice. This way, you can save water and won’t have to manually vacuum particles, which involves most of the hard work. But if water visibility is really compromised, then a pool flocculant should do the work much faster.

However, the thing with pool flocculants is that they are ideal for sand and DE filters because of the “recirculate” feature. This feature allows the water to flow out and back into the pool without flowing through the sand or the DE system. If your pool has a cartridge filter, then you are left with no choice but to go with a clarifier. 

And lastly, if you have a pool party scheduled tomorrow, then using flocculants should do the trick.

How to Use Pool Flocculants

Using pool flocculants is a simple enough process, but be ready to buckle down and do some manual work.

  1. Before doing anything else that involves putting flocculants in the pool, address the algae problem first if there is one. The reason for this is, if you put algaecide and floc together, they will cancel out each other’s effect.
  2. Be sure that you start at an above-average water level. You will certainly lose water in the process because of the vacuuming done later, so fill the water level up as high as you could. If the water level drops below the filter, the pump may not function at its best.
  3. Achieve the perfect water balance for flocculation. Many flocs work best at a neutral pH (7).
  4. Turn the pool pump off, change the valve to “recirculate,” and turn it back on.
  5. Follow specific instructions from the manufacturer. Dilute the flocculant to the proper degree and add the correct amount of floc based on the volume of the pool.
  6. Depending on the type of flocculent that you use, either pour it around the edges of the pool or place it directly into the skimmer.
  7. Put the pump in the “recirculate” mode to disperse the floc evenly into the pool.
  8. When it’s spread to every inch of the pool area, turn the pump off. This is where the magic starts. The pool should be still as a rock for at least eight hours as the floc pulls everything into a clump. 
  9. After keeping the water still and letting the flocculant do its thing, the sediments are now lumped at the bottom of the pool. At this point, the only thing that could get rid of them is a vacuum cleaner. But before doing that, turn the filter valve into “waste.” This will discard the water without going to the filter, preventing damage. Be careful not to disturb the water too much or the bundled particles separate and disperse into the pool again.
  10. The vacuuming process renders a lot of water going to waste so you need to replace all that lost volume again. After that, backwash the filter to get rid of all the residue that may have amassed.

How Often Should You Floc a Pool?

There is no definite answer to this, but based on the work involved and the water wasted, it is not a good idea to floc the pool often. A pool clarifier should do the trick every now and then when the water is slightly cloudy, but it could all be prevented by implementing and sticking to a rigorous cleaning regimen.

We are not going to discuss the specifics here, but some of the pool cleaning basics involve skimming, brushing, and vacuuming. You can do so manually but it will incur a lot of your time. You can hire a professional pool maintenance company, but that could hurt your budget a little.

Many pool owners have already found the answer to their everyday pool-cleaning needs: robotic pool cleaners. You can find a wide selection of models in the market, including ones that can climb and brush walls, collects gunk and debris, and everything needed to clean the pool. Regardless of the brand and model that you choose, robotic pool cleaners are guaranteed to cut your pool maintenance time in half!


In many situations, applying flocculants is the only way to restore the pool’s clear water. Such is the case when you need to use the pool immediately, or it gets too cloudy that you can’t see your feet from a depth of 36 inches. Otherwise, you may use a pool clarifier as it saves water and does not involve a lot of work.

Additionally, pool flocculants are best used if your pool has a sand filter or a DE filter. This way, you can use the “recirculate” feature to evenly disperse the floc and the “waste” feature to dispose of the water without exposing the filter to gunk and debris. 

As you can see, both flocculants and pool clarifiers do their jobs, but they accomplish it a little differently. Regardless, if you do want to clear up your murky pool water in a flash, just follow the procedures outlined above, and you’d be able to enjoy a sunny day in the pool in no time!