How to Get Rid Of Phosphates in Spas and Hot Tubs

Phosphates can accumulate quickly in spas and hot tubs, causing water clarity issues and reducing the efficiency of sanitising chemicals. Keep reading to learn how to get rid of phosphates in your spa water.

Keeping your spa or hot tub water well balanced and clean can be hard enough as it is without pesky phosphates intensifying the common spa pool problems you may be facing.

Although phosphates are simply the naturally occurring form of the element phosphorous, they act as fuel to microorganism growth and contribute to a myriad of problems in your spa water. These can include discoloration of water, and an increased demand for spa pool chemicals such as chlorine and bromine.

If left untreated, algae can also form and feed on the phosphates in your spa water.

Understanding phosphates is an important step to achieving consistently clear and sparkling spa water.

In this article, you'll learn:

What Causes High Phosphate Levels in a Spa Pool?

Phosphates are one of the most common naturally occurring elements on earth and because they are essential to life, they are practically everywhere. High phosphate levels are caused by the introduction of foreign organic matter into your spa water - things like dust, dirt, leaves, cleaning products, personal care products and body oils.

Your spa pool may have high phosphate levels if one or more phosphate introducing factors occur within a short period of time, or if your water has not been cleaned in a while after regular use.

Most phosphates come from natural materials, particularly those that are decaying. So, if you have not kept your spa water clean from natural debris, then that could be the cause of phosphates building up in your spa water.

Are Phosphates Bad for My Spa Pool?

Phosphates are only a problem for your spa pool if their levels are too high. Safe phosphate levels should not affect you or your spa pool as they are naturally occurring elements that are beneficial to sustaining life.

However, high phosphate levels can become a serious problem, particularly in a saltwater system, as phosphates can contribute to scale build-up on the electrodes of the system impeding its ability to produce chlorine.

Phosphates are also a wonderful source of food for algae and if left unmanaged can contribute to excessive algae growth.

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How Do Phosphates Get Into Spa Water?

You can accidentally enter phosphates to your spa pool water simply by getting into it, but some common sources include bird droppings, dirt, rainwater runoff, decaying insects, or soil.

Here’s something that you might not expect:

  • High phosphate levels in your spa pool may come directly from your water outlet!
  • This is because unless you have a phosphate-free water source, most water is abundant with phosphates.

Do Phosphates Turn a Spa Pool Green?

If you are struggling with green spa water or cloudy water, you may notice that your phosphate levels are through the roof. However, this is not because phosphates turn the water green, but because phosphates act as a fertilizer for unwanted algae blooms causing an algae outbreak.

Excess algae growth in your spa water is what will turn your hot tub water green. It may go hand in hand with foamy water too if your chlorine levels aren’t optimal, as foam in a spa pool is caused by excess debris, affecting algae growth as well.

How Do Phosphates Affect Chlorine?

High phosphate levels in a spa pool increase chlorine demand as they contribute to algae growth. The more debris and algae in your spa water, the less free chlorine will be available to keep your spa water sanitised as all the available chlorine is working to break down the algae.

When there is an algae bloom, shocking the water to break down the algae may also have a counterproductive effect on chlorine levels. This is because algae release phosphate back into the water when breaking down.

As all the algae are killed, phosphate is released called orthophosphate, spiking the phosphate levels in the water. This sudden increase in phosphate creates an environment rich in nutrients for more algae to grow, followed by a much higher chlorine demand.

How To Get Rid Of Phosphates in a Spa Pool

To get rid of excess phosphate in a spa pool it is vital to tackle the problem at the source first before trying phosphate removal products. Phosphate is not a problem on its own but is generally a result of too much debris or load in your water for your chlorine to manage.

Start with determining what is causing the high phosphate levels in your spa pool. Some common causes of high phosphate levels include unbalanced water, excess debris and dirt, and a phosphate-rich water source.

However, keeping your spa pool as clean as possible by regularly removing debris and avoiding algae growth is the best way to keep phosphate levels in the safe range, even if your water source is phosphate-rich.

Once your spa water is well balanced, you can use a phosphate remover to lower your phosphate levels even more and help you maintain these safe levels.

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testing spa water alkalinity and pH

What Should Phosphate Levels Be in a Spa Pool?

Some phosphate in your spa water is only natural and should not be a cause for concern if it remains within safe levels.

In general, provided that your phosphate levels remain below 1000 ppb (parts per billion), the phosphate content in your spa water should not impact algae growth - which is the main concern for high phosphate levels in your spa pool.

Do You Really Need Phosphate Remover?

Despite what some spa pool chemical sales reps will tell you, phosphate remover is not a necessity to achieve a clean and clear spa pool. Phosphate remover can actually be more problematic and toxic in your spa pool than phosphates themselves.

To get clean water in your spa pool you are far better off simply maintaining your chlorine balance, keeping algae at bay using algaecide, using shock treatments on your water, and physically keeping the water clear of debris.

Once these four methods are in place, if your phosphate levels are still higher than you’re comfortable with you can then use a phosphate remover treatment to cut down the rest.

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Frequently Asked Questions About Spa Phospates

Will high phosphates make a spa pool cloudy?

Yes, high phosphates in spa pool water can make a spa pool cloudy due to the fresh algae growth feeding off the phosphates. New algae appear dull in color, making the water look cloudy. However, one of the most common causes of cloudy water is high calcium levels.

Do phosphates cause algae growth?

Yes, phosphates act as a great nutrient fertilizer for algae growth. However, for phosphate levels to contribute to algae growth, the phosphate levels in the spa pool water must reach 1000 ppb.

Does chlorine kill phosphates?

No, chlorine does not kill phosphates. Phosphates are not living organisms, but they do act as nutrients to microorganisms like algae which can be broken down by chlorine.

Do I need phosphate remover for my spa pool?

Phosphate remover is not a necessity for a spa pool. However, it can work well in conjunction with good spa water management to eliminate the excess phosphates released when microorganisms are broken down after a chemical treatment.

Do phosphates eat chlorine?

No, phosphates do not eat chlorine. However, phosphates do decrease the available free chlorine found in your spa pool, increasing the chlorine demand of your water. This is because excess phosphate is a powerful nutrient for algae and can trigger algae blooms.

Got more questions?

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