Phosphate Remover

Pool Phosphate Remover - What Does It Do? Ultimate Guide

Phosphate removers are a unique chemical that are less often discussed than other pool treatments. These products work by removing phosphates from your water, which are an essential element of algae and bacteria growth.

In this article, we will talk about what phosphate remover for pools does, when you should use it, and how to add it to your pool. We’ve also included a guide on our recommended phosphate removers near the end of the article in case you need help choosing a product.

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What Are Phosphate Removers?

Phosphate removers for pools are composed of natural, rare earth compounds (typically lanthanum chloride) that bind to the phosphates in your pool’s water.

This then causes the phosphates to become insoluble particles that are capable of being removed by your pool’s filtration system. But what are phosphates, and why would you want to remove them?

What Are Phosphates?

When referring to swimming pools, phosphates are compounds that are left behind in your pool by organic waste.

This organic waste can include leaves, twigs, grass clippings, lawn runoff, urine, sweat and more. For things like twigs and leaves, the longer they sit in your pool, the more they break down and release phosphates.

Too many phosphates in a pool is a bad thing because algae and bacteria are capable of feeding on them.

While phosphates alone will not cause an algae infestation (adequate free chlorine levels prevent this), if algae does start growing, it is more likely to spread rapidly when high phosphates are present.

When To Use A Phosphate Remover

Phosphate removers are typically recommended for use in a pool when your phosphate levels exceed 500 parts per billion (ppb), or 0.5 parts per million (ppm).

Because there is no such thing as too little phosphates in pool water, other sources may recommend lower levels of 0.2ppm or less.

To test the amount of phosphates in your pool, use an appropriate test kit. We like the phosphate test strips because they are easy to use and deliver fast results. Phosphate test kits may return results in ppb, ppm, or mg/L (ppm and mg/L are equivalent).

It’s important to note that phosphate removers cannot be used to clear a green pool, and they are also not a substitute for proper algae removal treatments.

It is only efficient to use a phosphate remover in your algae treatment process once all active algae has been killed off with shock treatments and an algaecide has been used.

Phosphate removers are similar to algaecides in that both of these products work best when used to prevent algae infestations from forming.

However, unlike algaecides, phosphate removers will not have any effect on living algae in your pool’s water. These products only remove the algae’s food source.

It is possible for a pool with lots of algae present to show a very low amount of phosphates. This occurs when the phosphates in the water have been consumed by algae and are bound up within their cells.

Once the active algae is killed off and begins to break down, these phosphates are released back into your water, where they can react with the phosphate remover.

How To Use Phosphate Remover In Your Pool

#1 - Test Your Phosphate Levels

If you have not done so already, test the phosphate levels in your pool. Remember that organic debris can cause this number to rise, so you should take care to net out any leaves or similar items from your water as you work to lower these levels.

#2 - Choose A Phosphate Remover

Depending on the amount of phosphates present in your pool, choose an appropriate strength of phosphate remover. When shopping for a phosphate remover, look for information about the amount of phosphates it is capable of removing.

Phosphate removers are available in strengths that remove up to 6000 ppb or 6.0 ppm of phosphates, but it is not necessary to use such a strong product if you have lower levels.

Near the end of this article, we’ve included a guide of our top recommended products, sorted by potency for your convenience.

#3 - Add And Circulate The Product

Follow the dosing instructions provided on your product packaging to determine how much product to add to your water. Most phosphate removers are sold as a premixed solution and can be added directly to your pool’s skimmer box while the pump is running.

Phosphate removers can occasionally cause cloudy water. This occurs when the phosphates are pulled out of solution and combine with the product to form solid compounds. This cloudy water usually only lasts for up to 24 hours and should resolve itself as you run your filter.

On some occasions, this cloudiness can last for a few days, but this is rare.

After circulating your water for a minimum of 24 hours, you should then retest your phosphate levels and find them significantly reduced.

Once you have lowered a buildup of phosphates, you may opt to use a maintenance dose of a mild phosphate remover on a regular basis to prevent a large buildup from happening again.

We typically recommend Lo-Chlor’s line of phosphate removers, as this line is available in many strengths. All of the phosphate removers in this collection are made of nontoxic polymers and rare earth compounds that are safe for your pool’s equipment and swimmers.

These products are mostly able to achieve their intended effect in a 24 hour period, do not require vacuuming, and have been designed to resist filter clogging, unlike other similar lines of products.

For Phosphate Levels Below 1 ppm

For phosphate levels below 1 ppm, we recommend using Lo-Chlor Starver. This product is among the most mild phosphate removers available and is gentle enough that it does not cause water cloudiness.

This product is also the best choice for use as a regular maintenance product, should you opt to use one once your phosphates have been lowered.

The Zodiac Phosphate Remover is another low strength option.

For Phosphate Levels Between 1-2 ppm

For phosphate levels between 1-2 ppm, we recommend using Lo-Chlor Starver M. This product maintains all the great features of the original Starver while coming in a more concentrated formula.

For Phosphate Levels Above 2 ppm

For phosphate levels above 2 ppm, we recommend Lo-Chlor Starver X. This high-strength phosphate remover can remove up to 6 ppm of phosphates per dose, making it the most concentrated formula available.

Due to the strength of this product, water may turn cloudy for a brief period of time during usage, but this will resolve on its own after approximately 24 hours of filtration time.


Phosphate removers are an important part of swimming pool maintenance that many pool owners have never heard of. While these products do not treat algae directly, using them as directed can prevent algae from spreading rapidly beyond control.

Do you have any questions about what phosphate remover for pools or how to use them? Get in touch with us in the comment section, we would love to help!

Louis from Pool Advisor


A chemical engineer by trade, Louis is committed to debunking myths in the pool industry by explaining the underlying chemistry and making it accessible to all.