Do I Need To Remove Phosphates From My pool

 The newest miracle chemical this year for your swimming pool is the Phosphate Eliminator that removes Phosphates that some say is the main source of food for Algae. There is one problem with this theory, It’s just not true. Does Eliminating Phosphate from your pool matter.  Do I need to remove phosphates from my pool?

No, While phosphates are a concern in terms of environmental impact, they’re much less of a concern in swimming pools. Utilizing a proper sanitizer & a preventative algaecide will prevent algae regardless of phosphate levels at a much lower cost. 

Your Backyard Swimming pool is not a balanced ecosystem that uses Biological functions in any matter, shape or form. Your Pool is a Chemically controlled process that is treated or sanitized to prevent any life that depends on Biological functions to exist.

What Do Algae Eat


Algae are plant-like organisms that occur in nature that containing chlorophyll that traps the light from the sun. This light energy is then converted into food molecules in a process called photosynthesis. You remember that from 6th-grade Biology. Most algae store energy as some form of carbohydrate complex sugars for food.

Algae can be small and microscopic one cell plant life or big multi-cellar organisms. They can live in freshwater or saltwater. They can live on hard surfaces like rocks, trees or walls, floors and ladders in your swimming pool if you let that happen and don’t have stable chemistry in your pool water.

The cell walls of Algae are generally made of cellulose and can also contain pectin, which gives algae its slimy feel.

They are grouped according to the pigment or color that they use in Photosynthesis, the makeup of their cell walls and the types of carbohydrate compounds they store for energy, along with the types of flagella whiplike structures they use for movement.

The colors of different algae types are because of their particular mixtures of photosynthetic pigments, which typically include a combination of one or more of the green-colored chlorophylls as their primary pigments.

Algae are similar to land plants and convert Carbon Dioxide and water to Oxygen. They play a crucial role in the Biological existences of the earth which all starts with the Sun. and Photosynthesis. Algal Blooms can be detrimental in Fish Aquariums that are biological ecosystems dependent on oxygen to function. 

How to Prevent Algae in pools


A good maintenance swimming pool shouldn’t have too many problems with Algae blooms and the time and effort it takes to get it back. To prevent Algae from inhabiting your pool you need to follow some simple instructions:

  1. Proper Sanitizer Levels
  2. Proper Circulation System
  3. Proper Maintenance Plan

In a well-maintained pool, usually, Algae will sneak up on the pool and starting as Surface Algae. This is quite normal even if you have the chemicals right on point. This could happen along with the steps or around the ladder in an inground bigger pool it could be in the crevices and holes that Algae can hide and colonize. Still, If you do have visual Algae:

  • Run the Filter off the timer 24-7
  • Test Alkalinity first– Adjust accordingly
  • Test PH- Adjust that accordingly
  • Brush the pool with a long handle Nylon Brush and concentrate on the pool sidewalls and bottom.
  • Shock the pool when the Chemistry is Right
  • Observe the Pump Pressure occasionally to see if it goes up and needs Backwashing
  • The pool should turn a white cloudy billowing color with enormous amounts of suspended matter.
  • Add Algaecide. to the pool distributing evenly across the surface of the pool.
  • Brush– Not only will it scrub the small nooks and crannies on the wall and the pool bottom but it will mix the chemical you are adding.
  • Add a Clarifier or Flocculant according to directions and let the pool settle down
  • Run the Vacuum the next day after you added the flocculent making sure to Waste the thickest amount of material at the bottom. Do not run it through the filter.
  • Continue to run the Filter off the Timer until you see the pool turn blue
  • Take Test Readings-it’s Over

The causes of algae Bloom in swimming pools is most likely due to the chemistry of the pool. If the alkalinity is out of range then PH has no cushion and any bump could cause the PH to tumble and the ball starts to roll.

First Alkalinity then PH then the Chlorine levels on a warm day with the sun burning any residual that left, you can have algae bloom pretty fast. It will even happen to a guy like me.

If it’s not the chemistry then I would check the filter. Sand filters need to have sand replaced every 3- 5 years. Most likely though, a quick Algal bloom would happen if the chorine depletes and the temperatures are summer hot.

I would still vote on the chemistry of the pool. It’s invisible and can change fast especially in August. The reagent could have gone bad. There is a shelf life on all chemicals. The reagent inside the Test Kit is no exception to the rule. Keep all reagents out of the sun and in a cool dry area. Replace reagent every year. Keep the kit but get rid of the Reagents.

Did the pool turn green because of Phosphate levels in the water? I highly doubt it. I think Phosphate levels in swimming pools were probably more prevalent in the 70’s right up till the government banned them in detergents, I believe in the 1990s.

Detergents and cleaners used phosphates until the higher levels were causing Algae Blooms in effluents of Wastewater Plants across the country. Nutrients were overloading the aquatic systems and causing low oxygen rates resulting in fish kills. It had nothing to do with Swimming Pools.


Homemade Phosphate Remover for Pools


  • If you have a multi-port valve on your filter, shut off your pump and turn the valve to Recirculate or Recycle. This will mix the floc around without filtering the water and is the best way to mix the contents of your pool.
  • Add the recommended dosage of liquid or powder flocculant to your pool. Remember there are approximately 7,5 gallons of water in 1 square foot of pool water.
  • Circulate your water for 3 hours, or as long as it takes for your pump to turn the pool over. Then shut off your pump and let it sit overnight. The floc will bind to the algae, then settle on the pool bottom floor.
  • In the Morning-Turn the multi-port valve Setting to Waste so dirty water doesn’t blast back into your pool through your return lines. Hook up your backwash hose to the Backwash/Waste port. Direct your waste water appropriately.
  • Vacuum your pool. Work slowly to make sure you get all the thick sediment off the bottom. If the water gets too cloudy, you may need to stop and allow the particles to settle again before continuing to vacuum.
  • Add water while you’re vacuuming because you’ll be removing quite a lot
  • Shock immediately after vacuuming to eliminate any remaining algae. You may also want to brush the pool
  • Brush the sides and floor before shocking.
  • Run your filter until the water clears.

Are Phosphates Harmful to Humans?


Phosphate is Safe in fact it is Very Safe. Found naturally in nature. Phosphates are not toxic to people or animals unless they are present at very high levels. Digestive problems could occur from extremely high levels of phosphate. Phosphates are added to drinking water in some states in the country to prevent corrosion caused by copper and lead in pipes.

Phosphate is one of the key elements on earth that is necessary for plant life growth. They are still allowed to be added to cleaning products and some dishwasher Detergent. The problem comes when an overload of nutrients in streams and rivers like the nutrient, phosphorus which can help grow plant life such as Algae way too fast.

Because of this, Oxygen that is dissolved in water would be sucked out of the stream or river producing an anaerobic environment that would snowball killing fish and plant life that will decompose and will add more nutrients chemicals to the water and so on causing a snowball effect. That’s a Biological Problem Not a Pool Problem!

In a swimming pool, the water is chlorinated and if chlorinated properly there won’t be an algae problem, to begin with.

How do you know if there are phosphates in your pool? Just use the cheap test strips that come with pool kits and you’ll get some kind of idea. But some studies show that they really only affect pool algae growth at extremely high levels of 1,000 ppb (parts per billion) or more.

So, monitor the level at the start of the season but don’t get crazy about it or concerned when phosphate is present because it always will be present. it’s a natural element here on earth and is added to drinking water. There always will be a trace of it in water.


Phosphates in Swimming Pools


If you are losing sleep over this Pool Store developed dilemma then you should do a few things to offset your chances of Phosphate turning your pool green. 

  • Skim your pool with a pool skimmer-this will drastically improve your odds of less Phosphate in your pool and also you should be skimming your pool.
  • Brush the sides of the wall and the bottom of your pool– This should be done a couple of times a week
  • Clean out the Skimmer Boxes where twigs and leaves can collect
  • Keep your pool covered when not in use. (that ain’t gonna happened)
  • Keep your Pool’s Alkalinity, PH & Chlorine Residual in Check-Like you are supposed to.
  • Use an Algaecide Prohibitor-weekly or twice per/month. Algaecide Inhibitor is a great inexpensive proven product especially in those “Dog Days Of Summer 
  • Read my article on MyWaterEarth&Sky called  How to make the Water in your Swimming Pool Soft and Silky with my tips on keeping your pool water feeling and looking great all season.

Pool Maintenance is more hump work than technical ability. Some problems can be fixed without taking out your credit card. Most times, your Pool just needs some good old fashion Hump Work.

As many years as I have been taking care of my ‘Ole Concrete’ Inground pool, I have never witnessed a high Phosphate result on my testing equipment.

“Take some water out of the pool that will also lower the Phosphates level. If you are worried about it.”

Maybe I’ve just been lucky all those years. Maybe I wasn’t looking for one. “Keep your wallet in your pocket and be the master of your swimming pool this year.”


Related Questions:

Do Phosphates Deplete Chlorine Levels In Your Pool?  No, Phosphates maintain their perfect oxidation levels all by themselves, they don’t react with chlorine at all. Another untrue fact to push you to buy a product that eliminates Phosphate.

Are Phosphates used in Fertilizers? Yes, There are Phosphates that are used in some fertilizers and other Farm Chemicals that are used in Agriculture. It is unstable in its a basic state much like a lot of chemicals (until it is mixed) and is highly toxic.

Will Clarifiers or Flocculants settle out Phosphates? Yes, With the right mix and the proper timing a flocculant can be used as it would be in the scheduled general maintenance of the swimming pool or after an Algal bloom and will remove Phosphates.


Jim has written over 300 articles on the World-Wide Water Problems & Solutions.

He has over 30 years in the Water/Wastewater & Water Filtration Business as a Consultant and in Operations He is a member of (IWA) International Water Associations and  the India Water Portal & The Delaware Riverkeepers Network 


Author/Editor, MyWaterEarth&Sky

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