Phosphates in Pool Water – All You Need to Know

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Although many things can make your pool water green and cloudy, high phosphate levels are one of the most common sources of these pool problems.

High phosphate levels will come with all kinds of pool problems, including making it hard to keep your pool chemistry in balance.

However, to deal with this common pool problem, you need to understand what phosphates are, where they come from, and how to control the level.

What are Phosphates?

In chemistry terms, phosphates are naturally occurring and non-metal elements that will contain phosphorous, oxygen, and hydrogen. Sometimes they also include other compounds depending on what they combine with in the water.

Phosphates are organic materials that will occur naturally in pool water. They come from phosphoric acid, dead leaves, lawn fertilizers, and many other sources in and around your pool.

Also, phosphates are widespread, and almost every living organism and biological system will have them.

Where do Phosphates Come From?

Phosphates are highly abundant compounds, so it is not always easy to trace where they come from in your pool water. However, here are some of the most likely sources of phosphates in your pool water.

1. Human Sweat and Body Detergents

Swimmers are responsible for the highest amount of phosphates in pool water. Human sweat, urine, and skin can add a significant amount of phosphates to the water.

Also, hair products and body detergents contain phosphates, and hence swimmers often transfer them to the pool water as they swim.

2. Water Runoff

When it rains and water runs off your yard into the pool, it will add phosphates. Things you use to keep your yard in great shape, like fertilizers and other garden care products, contain phosphates. Most of these phosphates collect in the soil get into the pool with the rainwater.

3. Organic Pool Contaminants

If you have trees and other plants close to your pool, they might be the reason your phosphate levels are high. These plants add organic matter like twigs and leaves into the pool that contains lots of phosphates.

4. Municipal Water

Sometimes the high phosphate levels come from using municipal water in your pool. During water treatment, phosphates help minimize the levels of compounds like copper and lead.

Besides water treatment, some products you use to clean and maintain your pool, like pool stabilizers, contain phosphates. Therefore, these products can also raise phosphate levels in the water as you use them more and more.

Dangers of Phosphates in Pools

While it is not easy to have a pool with zero phosphates, and it is even not ideal for your pool chemistry, too high levels can be dangerous. Here are a few issues that result from having high phosphates levels in your pool.

1. Phosphates Promote Algae Growth: Algae is one of the most annoying pool problems. Algae will thrive and spread faster if your water has high phosphate levels, making it more complicated and expensive to remove.

2. Increased Chlorine Demand: Phosphates will use up the chlorine in the pool water much faster, meaning that you will need to keep adding more to keep the pool sanitized. Hence, pool maintenance will be more hectic and expensive for you.

3. It Can Affect Your Health: When the levels of phosphates in the pool water get beyond 1,000 ppm, it can pose a significant health risk. Also, like high levels of chlorine, it can cause skin and eye issues.

How to Test Phosphates in Pools

The best way to test phosphate levels in pool water is by getting a phosphates testing kit. With a good kit like the AQUACHEK 562227 One Minute Phosphate Test Kit, you can quickly check the phosphate levels by observing the test strips’ color change.

While these test strips are super easy to use and inexpensive, they are not the only option for testing phosphate levels. You can also take a water sample from your pool to your local pool supply store for testing.

How do We Control Phosphate Levels in Pools?

Once you test the phosphate levels on your pool and determine the levels are high, it is essential to intervene to ensure your pool remains in good shape. Luckily, there are several ways of controlling phosphate levels in pool water.

1. Skim Pool Water Regularly

Skimming your pool is one of the most crucial aspects of maintenance and perhaps what you need to do most often. However, it is even more helpful if you have a problem with high phosphate levels.

By removing leaves, twigs, and other organic contaminants floating in the pool, you will eliminate one of the primary sources of phosphates in pool water.

2. Scrub Pool Walls/Floor and Clean Filters

Skimming will help you remove any organic matter floating on the pool, but some can still be on the pool walls and floors. Therefore, it is also crucial to scrub and vacuum the pool walls and bottom thoroughly.

Additionally, it would be best if you also cleaned your filters regularly. Filters will trap all kinds of pool contaminants, most of which can increase the phosphate levels in the water. Therefore, by cleaning the filters, you can ensure that phosphates are not cycling through.

3. Use Phosphate Remover

A phosphate remover will use special compounds like rare earth metals to bind to the phosphates in the pool and remove them.

There are many chemicals for removing phosphates, but it is crucial to choose one keenly for the best results. The Natural Chemistry Phosfree is an example of a highly effective phosphate remover.

However, it is crucial to make sure that you use phosphate removers sparingly, as using too much poses a health risk and can also throw your pool chemistry off balance.

4. Add Calcium

If you also need to raise your pool calcium level besides controlling phosphates, you can solve both problems by adding some calcium. Calcium has positive ions that can bind to the negative phosphate ions and ensure little is available to feed algae.

Bottom Line 

While it is easy to overlook the impact of phosphates in your pool, you should not, as they can significantly impact your overall pool chemistry.

Keeping the level low by skimming and cleaning your pool regularly and ensuring the filters are always debris, and dirt-free is crucial.

That said, tracking phosphates as you monitor other things like pH, alkalinity, and chlorine level is the best way to ensure they never cause you problems.