Phosphates can enter your pool from a multitude of sources, and most pools have at least some level of phosphates in the water. They may or may not pose a problem with your particular pool water chemistry, but if you are having extreme water clarity or pool algae problems, and - your filtration is sufficient and water chemistry is very good - you may have a pool phosphate problem.
Where do Phosphates Come From?
- Found naturally in soils, animals and leaves
- Major component of lawn and garden fertilizers
- Shampoos, soaps and detergents on skin, hair and suits
- Aging water treatment systems add phosphates to slow pipe corrosion
- Some pool metal removers contain phosphates.
Problems from Phosphates in Pools?
- Phosphates are a tasty form of food for algae, leading to algae blooms
- Phosphates occupy some chlorine, making your chlorine less effective
- Phosphates can attach themselves to salt cells, reducing performance
- Phosphates act as dispersants, leading to cloudy pool water
- Phosphates can cause pool stains or clog sand filters at very high levels
Symptoms of High Phosphate Levels?
- Repeated algae outbreaks
- Repeated problems with cloudy water
- High levels of Free Chlorine required for clear water
What Level of Phosphates is Too High?
- Manufacturers suggest 200-300 ppb (parts per Billion) is too high
- Servicemen suggest that 3000 ppb may be too high
- Chem Geek says it doesn't matter, if Free Chlorine is 7.5% of CYA level
How to Test Pool Water for Phosphates
Lowering Pool Phosphate Levels
- Add a Phosphate Remover
- Floc the pool with Alum, Aluminum Sulfate
- Add a weekly Algaecide Treatment
- Maintain a higher FC to CYA ratio
- Use ZeoSand instead of regular filter sand
Note that lowering pool phosphate levels will not remove algae from the pool, so the first step in addressing any potential phosphate problem is to make sure the water chemistry is balanced, and the level of cyanuric acid (aka stabilizer or conditioner) is around 50 ppm, and the chlorine level is maintaining at 2-3 ppm.
In some cases, changing your pool filter media (sand or cartridges) may be needed for a complete return to normal conditions. Heavy algae outbreaks and lots of chemical treatment tends to spoil filter sand, and reduce filter cartridge life.
Until next time;
SPP Pool Expert