Phosphate Removers

Reasons for use

Phosphate Removers should be considered an insurance policy, not a required part of pool care. If a user struggles to maintain the FC/CYA ratio, using a phosphate remover may help the user avoid an algae outbreak. Algae will occur if chlorine isn't added, but it will take longer to develop with a low phosphate level.

Please don't use the rubbish phosphate removers from the pool stores. The stuff is so watered down that it's a joke and often contains a clarifier that could mess with your filter. Use a quality product like Orenda 10,000 or Seaklear. While the prices are slightly higher, it'll reduce your level a fair amount more than the rubbish from the store. The threshold limit for phosphate removal is around 1000ppb (1ppm), there is no point in removing phosphates if your phosphate level is below a 1000ppb.

If you have high levels of phosphates, please expect cloudy water. This occurs because the phosphates are being removed from the water and must be filtered out. Removing phosphate early in the year or when the pool won't be used is wise. Don't add phosphate removers just before your huge 4th of July party, and then cry because the water is cloudy.

Also, you may get sediment around the bottom of the pool that you will need to slowly vacuum to waste if you can, or your filter, or have your pool cleaner get it. The phosphate remover creates something like a “floc,” with the lanthanum in the remover reacting with both phosphate and carbonate. Eventually, the lanthanum is fully converted to lanthanum phosphate, an insoluble compound at normal pool pH. When the lanthanum phosphate forms, it may capture suspended fine particulates in the water, and then that conglomeration of “junk” settles to the bottom. Thus, the phosphate remover acts like a floculant. It’s not intended to be a floc but acts that way.

Test with your phosphate test kit. A good kit costs about $20, and the results are reliable.

Don't bother using phosphate removers if you have green water. First, you're unable to test as algae does alter your readings, so you'll likely waste some product and overdose. Second, algae contain phosphates, so as you kill the algae, the phosphates WILL be reintroduced into the water........so you're just going to run in circles. Instead [1] the pool THEN worry about removing phosphates.

Don't assume a low level of phosphates will completely prevent algae. Continue to follow the FC/CYA Chart. Use phosphate removers ONLY as insurance in case you mess up.

How do Phosphates help Algae Thrive?

Nitrogen (N), phosphorous (P), and carbon (C, mainly in the form of sugars) are all necessary for life. If any one of those elements is missing, life can not exist.

Micronutrients such as potassium (K), calcium (Ca), magnesium (Mg), and iron (Fe) are also necessary but in much smaller quantities. None of those elements can substitute for one another; they are all used in different ways and are all required.

When water is deficient in nutrient sources, it is called an “atrophic” condition - meaning it is missing nutrients. When water has too much of any nutrient, it is called a “eutrophic” condition. Eutrophication of water leads to uncontrolled and unhealthy algae and bacterial blooms.

Pool water is eutrophic but also aseptic because of the chlorine sanitizer in it. So, while properly chlorinated pool water will not have significant algae or bacterial growth, it is always susceptible to biofouling (unrestricted growth) because of its high nutrient content.

Reducing nutrient levels by chemical removal (precipitation and filtration) or water replacement will help reduce the incident rate and severity of biological growth.

Phosphate removal is simply one strategy for making water atrophic.

Pool Must be Algae Free Before Dealing With Phosphates

Phosphate removers say that algae MUST be dealt with before dealing with phosphates. The instructions from the Orenda 10,000 say Algae in a Pool will result in a false reading.

With a full-blown algae outbreak, a phosphate test can be close to nil as all the available phosphate is incorporated within the algae. With all the phosphate being held by the algae, there is nothing available to remove. When the algae are treated and die, all the available phosphate stored in their cell walls and all the other nutrients are released back into the water, where a test will now show the true total value.

If you use a phosphate remover with algae and reduce your phosphate levels to zero, you’ll be disappointed when you clear the pool and test it again in a week. The phosphate levels will be high again.

Any pool store that suggests that a customer with a green/cloudy pool use a phosphate remover before clearing the algae problem is giving incorrect advice and just looking to sell expensive chemicals.

If you have algae in your pool water, forget removing phosphates and focus on using chlorine to kill the algae.

How to Test for Phosphates in Pool

When removing phosphates, the goal is to keep them as low as possible. So, it doesn't matter how high they are to start with or where the test maxes out. For the Taylor test, there is a high-limit version that goes up to 2000ppb, but it's not necessary. Just use water dilution if you max out to get a feel for where you are. Most commercial grades of PO4 removers can handle 10,000 ppb per 10,000 gallons of pool water per quart of product administered.

Taylor has the K-1106 phosphate test kit. The Taylor K-1106 test kit can test at phosphate levels of 0-1000 ppb or 0-6000 ppb. It has two different color comparator cards for the two tests.

Using Phosphate Removers

Lanthanum chloride reacts with the free, dissolved phosphate compounds to form a salt (precipitate) of Lanthanum and phosphate (lanthanum phosphate), which is not soluble in water. The chlorine ion from the Lanthanum chloride likely ends up bound to free sodium ions to form sodium chloride, table salt, which would dissolve in water. Lanthanum sulfate is also in these phosphate removers and reacts similarly with phosphate.

Lanthanum is classified as a rare earth element. It's not that rare in deposits; it's just difficult to mine and extract. Hence, phosphate removers with lanthanum compounds are relatively expensive and largely unnecessary if proper chlorine levels are maintained.

What's the Best Brand of Phosphate Remover?

One of the first cons of phosphate removers is the price. Orenda PR-1000 or SeaKlear phosphate removers are the most concentrated and the best value.

You can search for the best phosphate remover after purchasing a phosphate test kit and finding levels towards the “high” end. You will find there is a significant difference in quality between products. A liter of “Natural Chemistry” will only remove 2000ppb phosphates from a 10,000-gallon pool, while a product such as Orenda PR-10000 will remove 10,000ppb phosphates from a 10,000-gallon pool. Both are in the $40 range, while the Natural Chemistry is sold as a 2-liter compared to Orenda, which is sold as a quart. Regardless, the Orenda brand is considerably the better deal……but how costly is it to use?

For a 24,000-gallon pool with phosphates, about 1500ppb, around 15 ounces or ½ a bottle is needed. As expected, the pool became cloudy within minutes, which cleared up after a day of filtering. After adding an initial dose last year, another dose was needed once at the start of this season, which used 10 ounces. Ten ounces will be remaining after 2 years of use. If the pattern continues, the initial purchase of a $40-dollar bottle of Orenda phosphate remover will last roughly 3 seasons and make the product about $13 a season.

How Do Phosphates Get Into Pool Water?

While phosphates are found and added to pool water naturally, the bulk of the time humans add them.

• One common issue is runoff from fertilizer; however, there are other instances too.
• Many products, such as metal sequestrants, contain phosphates, and users will quickly find themselves with high phosphate levels if they continue to use them.
• Many cities use phosphates in the city water supply to help form a thin coating on the walls of the water pipes. This is to help reduce the risk of eroding the pipes.