Pool Flocculant vs Clarifier: What’s the Difference?



Flocculants and clarifiers often get mixed up in the pool business.

In this article, we’ll look at the characteristics that separate these two coagulants, and help you understand which one to use in your pool.

Short answer: Flocculant and clarifier both force tiny particles in your pool to clump together. Flocculant works faster, forms larger clumps, and requires vacuuming, while clarifier works slower and relies on your filter.

How Are Flocculant and Clarifier Similar?

Here are the similarities between clarifiers and flocculants:

They Look the Same

Whether you buy a clarifier or flocculant, it’s usually going to come as a small bottle of liquid that can be poured directly into your pool.

They can also be found in granular or powdered versions that are first dissolved in a bucket before adding to the pool, but these aren’t as practical and ultimately not nearly as common.

Either way, the substances themselves are often indistinguishable from one another, usually in the form of clear liquids (though some manufacturers choose to color their clarifiers and flocculants).

They Both Clear Up Cloudy Water

Flocculants and clarifiers are both coagulants, meaning they both form clumps of tiny, non-living particle matter.

In the context of pool maintenance, coagulation helps to restore water clarity by clumping tiny debris so it can more easily be removed from your pool, either through the filter or using a vacuum.

This process works the same for both substances; using positively-charged particles (the coagulant) to attract and “stick to” negatively-charged particles in the water (the contamination).

They’re Similarly Priced (But Not Really)

Whether you buy clarifier or floc, in liquid or granular form, you’re going to find them at similar price points.

However, while this price parity may be reflected on the product label, it’s important to factor in the different dosage requirements — with flocculants requiring considerably more product for a single use.

Overall, it’s not really an apples-to-apples comparison. We’ll talk more about this in the next section.

How Are Flocculant and Clarifier Different?

Here are the differences between clarifiers and flocculants:

Flocculant Works Faster

If you need to clear up cloudy pool water on a tight schedule, it doesn’t get much faster than floc.

Flocculant only takes around 24 hours to coagulate all the floating particle matter in your pool. It also forms larger, heavier clumps that sink to the bottom of your pool where they can immediately be vacuumed out.

On the other hand, clarifier takes several days to coagulate and it forms smaller clumps that continue to float around in your water, until they’re eventually processed by your filter.

Clarifier Works with Your Pump

Clarifier forms smaller clumps because it’s designed to work alongside and in tandem with your filtration system.

While it may take several days to work, your pump can be kept running and your water can continue to be circulated — which means all those clump formations will be forced through the filter and filtered out.

Flocculant works much faster and more aggressively than clarifier, but these benefits aren’t without consequence.

The size of the clumps formed by flocculant is generally too big to pass through your filtration system, so the pump needs to be turned off to avoid clogging and ultimately compromising your filter.

Instead, the clump formations must be removed manually (or using an automatic cleaner) before turning the pump back on.

Flocculant Works on Larger Particles

We’ve already touched on how flocculant forms larger clumps of debris, but there’s a little more to it.

Where clarifiers seek out very tiny particles in the water, flocculants work on a broader range of particles, including much larger debris that would otherwise be unaffected by clarifier.

Essentially, flocculant binds larger particles together that form even larger clumps of particle matter.

Clarifier is Used in Smaller Doses

All things equal, you don’t need to use nearly as much clarifier compared to flocculant.

This is because clarifier has a longer timeframe to work, only works on very tiny particles, and forms much smaller clumps. Overall, it’s a less aggressive chemical and the recommended dosage reflects that.

Below is an example from the same manufacturer, highlighting the difference in dosage can differ between them (and yes, that’s a 4x increase!)

Note: When you refer back to pricing, the difference in dosages makes clarifier far cheaper than flocculant despite the initial price parity.

Which One Should You Use?

If your pool is cloudy and you’ve eliminated all other potential causes, using either flocculant or clarifier may help.

Which one you should use depends on the severity of your situation and whether you have the luxury of time.

For example, if your pool is really cloudy and you want a quick turnaround, flocculant is the faster, more aggressive solution. However, it does mean turning off your pump and actively removing clump formations.

If your pool is a little murky and you don’t mind a few days of downtime, clarifier provides a slightly weaker but passive solution. As long as your filter is up to the task, the problem will largely take care of itself.

The Bottom Line

Flocculant and clarifier are fundamentally the same while still having plenty of notable differences.

In fact, it’s the differences in things like speed and aggressiveness that dedicate whether you should use one over the other, despite both promising the same outcome of crystal clear water.

Categories: Pool Care, Pool Chemistry