What are Phosphates and How Do They Affect Your Swimming Pool?

Sixty percent of pool owners experience two full algae blooms every season. So, what causes these blooms and how can we prevent them?

Algae blooms place a high demand on the chemicals present in your water and cost time and money in clean up. While everyone agrees on how to kill algae once it’s taken over your pool, PoolSupplyWorld will teach you how to take a proactive approach to preventing anything from blooming in your backyard except for your prized begonias.

With that, we’d like to introduce you to phosphates: a biological building block that is constantly being introduced to your water and nourishing algae spores. In this blog, we’ll explain how being proactive with phosphate-fighting chemicals – instead of reactive with huge amounts of chlorine shock and a scrub brush – will help prevent algae blooms and make your sparkling pool water the crown jewel of the neighborhood.

Algae and Other Scourges

We are fairly certain that if Sun Tzu had owned a swimming pool while writing “The Art of War,” history would have been irrevocably altered by his seminal chapter on conquering algae. Being that no such chapter exists, we’ll improvise. In order to understand how to defeat algae, you must understand what it needs to survive.

Algae reproduction depends completely on the presence of five key things:

  1. Sun
  2. Water
  3. Air
  4. Nitrates
  5. Phosphates
Yellow Algae in Pool

Phosphates are compounds of the nonmetallic element phosphorous and are a primary food source for aquatic plants, including all types of algae. Phosphate compounds are broken down into their simplest form, orthophosphates, in one of the following three ways:

  1. Oxidation (converting compounds in to oxides)
  2. Hydrolysis (decomposition by water)
  3. Enzymatic digestion

Regardless of how it happens, if phosphates are allowed to remain present in pool, spa, or pond water, they will be reduced to orthophosphates, which are the only form of phosphates that algae can digest.

Orthophosphate levels should remain below 100-125 ppb (parts per billion). Once levels exceed 200 ppb, algae becomes increasingly resistant to sanitizers, including chlorine shock. Excessive levels of orthophosphate, such as 1,000 ppb or more, should be brought under control with Natural Chemistry PHOSfree Extra Strength.

Who Invited Phosphates to the Party, Anyway?

The challenge with phosphates is that they are constantly being introduced into your swimming pool water. They are found in lawn and garden fertilizers, decaying vegetation, municipal water, cosmetic items on bathers, and even other pool chemicals. This means a fresh batch of phosphates enter your water when any of the following occur:

  • The wind blows dirt into your pool
  • Sprinkler run off from your lawn or landscaping enters your pool
  • Your water leveler puts fresh water into your pool
  • Leaves, twigs, or bark enters your water
  • You use chemicals containing TSP, or any amount of phosphoric, phosphonic or other phosphorous based ingredients to clean your pool

As such, you can never completely remove phosphates. Instead, we refer to it as maintaining a “near zero” level with a long-term solution that includes a blend of using Natural Chemistry’s PHOSfree products, regular water testing, correct sanitizer levels and limiting exposure to phosphates.

How to Maintain “Near Zero” Phosphate Levels

Pool Water Testing

Phosphate Test Strips

To effectively control phosphates, you must be able to measure their presence in your water. We recommend purchasing a test kit such as Natural Chemistry Phosphate Test Strips. These strips are highly accurate and measure orthophosphate levels in 10 seconds. They have the widest testing range available on the market, at 0 – 10,000 ppb. Water tests should be conducted weekly during peak swimming season and monthly during the off-season.

Regular Pool Maintenance

Pool Maintenance

The preventative measure of limiting phosphate exposure is taken by doing the following:

  • Remove leaves and organic material from the water as soon as possible
  • Vacuum and clean filters and pump baskets regularly
  • Be aware of the phosphate content of cleaners and chemicals used in and around the swimming pool
  • Don’t allow drainage from plants or the lawn to enter the pool

Phosphate remover myth buster:
We want to take this opportunity to clear up a myth about phosphate removers: they do not kill existing algae. Once bloomed, only superchlorination and/or an algaecide will do the job.

Natural Chemistry’s PHOSfree

Why PHOSfree is effective:

PHOSfree is added directly to the skimmer to remove phosphates on the filter and begins to work as soon as it is added. This potent and direct application is what makes PHOSfree so effective; if orthophosphates are removed from the pool or spa water but remain on the filter, your clean water will pick up new orthophosphates the next time it is circulated. PHOSfree will remove up to 900 ppb phosphate levels per application. If levels are higher than this, we recommend using Natural Chemistry PHOSfree Extra Strength, which is three times stronger than regular PHOSfree and is used in exactly the same way.

In order for PHOSfree or any phosphate removal agent to be effective, it must be added to a clean, properly balanced, algae-free swimming pool with clean filter media.

Why is PHOSfree desirable:

PHOSfree is a powerful, EPA-approved enzymatic formula that reduces phosphate levels to near zero. It is non-toxic and compatible with all sanitizers, filter types and pool surfaces. Unlike chlorine shock, swimmers can enjoy their pool or spa immediately after use. PHOSfree delivers highly effective results while being gentle on bathers and the environment.

Natural Chemistry PHOSfree products and their applications:

Natural Chemistry PHOSfree

Natural Chemistry PHOSfree brings phosphate levels to near zero and should be used when you first begin your phosphate management program. PHOSfree is non-toxic and will not cloud pool water. It is added directly to the skimmer and is compatible with all types of swimming pools, filters, and sanitizers.

Natural Chemistry Pool Perfect + PHOSfree

Pool Perfect + PHOSfree
Natural Chemistry Pool Perfect + PHOSfree is a weekly maintenance product that continually removes phosphates and organic contaminants from pool water. Pool Perfect is a powerful enzyme that reduces the need for maintenance by breaking down organic contaminants, surface oils and prevents scum lines. It continually cleans the filter media and makes water feel noticeably softer.

Natural Chemistry Pool Magic + PHOSfree

Pool Magic + PHOSfree
Natural Chemistry Pool Magic + PHOSfree is perfect for use when opening or closing your swimming pool. Pool Magic uses enzymes to break down organic contaminants and prevent organic staining while the pool is closed for the season. It likewise brings them under control after the pool is opened.

Now that we’ve covered what algae needs to grow, how phosphates are introduced into your water, how to maintain near zero levels of orthophosphates and the best preventative products to stop algae growth, check out our great selection of other chemical-free, natural solutions to pool and spa maintenance from Natural Chemistry.