The Ultimate Pool Owner’s Guide to Understanding Pool Phosphates

One of the most important steps in maintaining a swimming pool is to keep the pool water as clean as possible. This can be done by managing your water to maintain low pool phosphates level.

Having a green and murky pool water tells that the phosphate levels in your pool are likely to be too high. An excessive level of phosphates in your pool increases the likelihood of algae blooms while also making it more challenging to maintain the appropriate pool chemistry.

Swimming Pool Phosphates

Keep reading to discover more about phosphates, why it is essential to maintain low phosphate levels in your pool, and how to reduce the phosphate levels in your swimming pool.

What Are Phosphates in a Pool?

Phosphates are a form of inorganic phosphorus that is commonly found in swimming pools. When phosphates are introduced to water environments, algae growth can be stimulated.

When algae growth occurs, it can cause discolouration of the pool water and the growth of other organisms (i.e., fungi and bacteria).

This type of bacterial growth can release an unpleasant odour, create an unsightly appearance for your pool, increase skin irritation from chlorine contact, and make it difficult or impossible to maintain appropriate pool chemistry levels.

Phosphates may also enter your pool through dead leaves, lawn fertilizer, and many other sources. You can’t completely eliminate the phosphates from your pool water. However, your goal is to keep phosphate at very low levels so that it won’t help foster algae growth. 

Fun fact: Phosphates are a source of nourishment for algae and other aquatic plants. This is one reason having high phosphates fosters algae growth. However, a small amount of phosphate is not enough to promote algae development. According to research, you need 1,000 parts per billion phosphates in your water for algae to thrive and multiply. 

What Is the Risk of Having Too High Phosphate Levels in Your Pool?

There are several risks of having too many phosphates in the pool. Here are possible effects of having increased levels of phosphorus:

  • The risks of having too high phosphate levels in the swimming pool can increase the risk of algae growth and affect the ability to have a chlorinated pool.
  • The potential for algae growth may lead to eye irritation, skin rashes, and inflammation disproportionate on children and people with sensitive skin.
  • There is the risk of bacterial infections, which can be very serious if not remedied quickly.
  • A high level of phosphates may mean the building of foam and elevated pH.
  • The most significant issue with having high phosphates is that the long-term effects of this problem can be severe for human health and sustainability.  

How to Test Your Pool for Phosphates and Algae?

There are three ways to test for this. One of the easiest ways is to put your pool water on a leaf and let it sit for 24 hours. If blue algae are present, there will be a sharp colour change. 

Another way to test for algae is through a pool phosphate or algaecide solution, which can help combat these types of issues. To test for the presence of phosphates and algae in a swimming pool, you need to look for chemical reactions.

The presence of both phosphates and algae will cause the TDS or Total Dissolved Solids level in your pool to rise dramatically. You can also take the water sample of your pool and ask a pool professional to analyze it for you. 

Are You Supposed to Remove Phosphates?

Some pool experts and chemical salesmen promote the idea that algae bloom can only be managed by eliminating phosphates from your pool. This is simply not true. As a result, many pool owners overpay on phosphate remover, under the impression that this would fix the issue.

Unfortunately, merely applying a swimming pool phosphate remover will not solve the problem since other factors are involved in phosphates and algae.

Dirty swimming pool

Phosphates are not toxic or damaging. Eliminating them as a cure for the spread of algae is ineffective. Still, your best option is through regular maintenance, regular use of an algaecide to keep algae from sprouting, and periodic shocks of your pool to give it a very potent sanitizing wallop.

How to Lower Pool Phosphates Level?

For pool many pool owners, you don’t have to address phosphates always and for a very long time. However, you should be familiar with the several things that you can do to lessen the chances of phosphates building up. 

  • Keeping organic items out of your pool, such as leaves and yard trash, helps keep phosphate levels in check. When this organic material breaks down, they begin to release phosphates into the water. Ensure you thoroughly clean the skimmer after use to prevent reintroducing phosphates back into the water the next time you use it.
  • If you want to lower your phosphate levels in the pool, you might want to invest in a phosphate remover. There are also modern technologies that have been developed for handling phosphates in pools.
  • Adding calcium is also an excellent choice. However, the levels of your calcium should be maintained between 220-400 parts per million. Calcium (Ca) is a positive ion that will form a bond with phosphate, a negative ion, decreasing the amount of phosphate available for algae to nurture.
  • You should also do routine scrubs and vacuums to the floor of your pool since organic waste that settles to the pool’s bottom is easy to overlook. Remember to clean the walls and floors with a stiff brush and vacuum.
  • Check your filter regularly to ensure that it is in proper operating condition. While the filter will capture algae, leaves, and other debris, it will not remove phosphates from the water. If you clean out or replace your pool filter, you can ensure that phosphates are not cycling back through the pool water. 
  • Prevent algae build-up as much as possible.

How to Minimize Phosphates Levels in a Saltwater Pool?

Phosphates level in saltwater pools is generally high. To determine whether your pool’s phosphate levels are too high and your chlorinator isn’t generating enough chlorine, start by determining whether your chlorinator is appropriately sized for the size of your pool.

Even if it is, you may still need to supplement your pool with regular chlorine, depending on your location and the environmental circumstances in that particular area.

Finally, are you shocking your pool regularly to eliminate phosphate-producing organisms? Shocking one to two per month, and perhaps more when it rains, will help your pool stay in balance.

Pool Shock

Before you rush to the conclusion that you need to douse your pool with possibly hazardous phosphate remover, consider all the probable reasons that may lead to low chlorine levels.

More FAQs

Are You Safe to Swim in a Pool With High Phosphates?

Yes, swimming in a pool with high phosphates is safe if the following conditions are met: 

  • Chlorine levels must be high enough to neutralize the effects of the high phosphates present in your pool.
  • The pH balance remains at a specific limit, depending on what grade your pool has been graded for.
  • Your pool has a 10-3-5-5 day cycle schedule (meaning you shock it once per week for four weeks). This will ensure that algae doesn’t build up and prevents water quality from deteriorating because large algal growths are removed only temporarily until they grow back into big retches.

However, it is essential to monitor your phosphate levels since very high levels (in the range of 1,000 parts per billion) may harm your health.

How Harmful Are Phosphates for Your Pool?

Phosphates may not cause immediate damage to your pool, but they may cause issues down the road. For example, phosphate levels that are too high encourage algae development, which may damage the liner of your swimming pool.

In addition, phosphates eat up chlorine rapidly, making it tough to maintain your pool’s chemistry balance. As a result, pool maintenance becomes more costly and time-consuming. 

Checking your pool water chemistry regularly is how you can make sure that your pool remains healthy. For example, if phosphate levels increase over 100 parts per billion (ppb), you should use the techniques described above to bring them down.

Similarly, you should maintain your pool stabilizers between 30 and 50 parts per million (ppm). Cleaning leaves and other debris from your pool regularly by skimming, washing, and vacuuming can help avoid the accumulation of excessive phosphate levels in your pool.

Check out the following pool care guides for help in maintaining a clean and healthy pool. It will be fun for you and your family to swim in a clean and safe pool!

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About the author

Brian Anderson

The rather dry pool world out there is in need of some passion to make it shine. With the help of my son Ruben and his wife Maria our mission is to help you create the favorite spot of your house - your pool.

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