A phosphate remover is a specialized chemical treatment used in swimming pools to manage the concentration of phosphate compounds. Phosphates are a nutrient source for algae, and controlling their levels is a method of algae prevention that complements normal sanitation practices. The primary function of this chemical is to convert dissolved phosphate into a solid form that can be physically removed from the pool system.
Why Phosphates Accumulate in Pool Water
Phosphates are compounds containing phosphorus, a building block for all living organisms, including algae. While not harmful to swimmers, their presence provides a continuous food source for algae, even when chlorine levels are adequate. High phosphate concentrations allow algae to bloom aggressively, making it difficult to maintain water clarity.
External sources constantly introduce phosphates. Landscaping fertilizers are common, as runoff can wash the chemicals into the water. Decaying organic matter, such as leaves, grass clippings, and pollen, also releases phosphates as it breaks down.
Municipal water sources contribute to phosphate levels, especially where treatment facilities use phosphate buffers for corrosion control. Swimmers also introduce phosphates through bodily fluids, hair care products, sunscreens, and lotions. This accumulation necessitates a proactive removal strategy to prevent excessive algae growth.
The Chemical Action of Phosphate Removers
The effectiveness of most phosphate removers relies on precipitation, a chemical reaction that changes phosphate from a dissolved state to a solid state. The most effective products utilize rare earth elements, specifically compounds containing lanthanum, such as lanthanum chloride or lanthanum sulfate. Lanthanum ions possess a strong affinity for phosphate ions.
When the remover is introduced, lanthanum ions bind tightly to the dissolved phosphate ions, creating an insoluble compound called lanthanum phosphate. This reaction effectively removes the phosphate from the water solution. The resulting lanthanum phosphate is a micro-fine solid, or precipitate, that often resembles a flocculant.
The formation of this heavy, insoluble solid allows the phosphate to be physically captured and removed. These particles are either caught by the pool’s filter media or settle to the bottom. This mechanism starves the algae by eliminating its primary nutrient, offering a sustainable approach to prevention.
Step-by-Step Application of the Remover
Testing and Dosage
Application begins with accurately testing the water to determine the current phosphate concentration, measured in parts per billion (ppb). Levels exceeding 300 to 1,000 ppb generally warrant treatment, as these concentrations increase the risk of algae blooms. Based on test results and pool volume, the correct dosage is calculated according to the manufacturer’s instructions.
Application Process
Before application, clean or backwash the filter to maximize its efficiency in capturing the precipitate. With the pump running for proper circulation, the measured chemical is slowly poured into the pool, typically near the return lines or skimmer. This ensures the product is distributed throughout the water column for a complete reaction with the dissolved phosphates.
Circulation and Filtration
A temporary cloudiness or milky appearance is a normal effect following application. This cloudiness indicates that the chemical reaction is occurring and the insoluble lanthanum phosphate precipitate is forming. Continue running the circulation and filtration system for at least 24 hours after application to filter out the maximum amount of precipitate.
Cleanup and Maintaining Low Phosphate Levels
Once the phosphate remover has circulated and the precipitate has formed, the final steps involve physically removing the solid material. The fine particles will either be trapped in the filter media or settle on the pool floor. The filter must be cleaned or backwashed after the treatment period to ensure the captured phosphate compounds are completely eliminated from the pool system.
If a significant amount of precipitate has settled on the bottom, it should be carefully vacuumed, ideally to waste, to prevent the material from returning to the filter. After cleanup, the water should be retested to confirm that phosphate levels have been reduced to an acceptable range, often below 100 ppb. If levels remain elevated, a second, smaller treatment may be necessary.
Preventative habits are the best defense against future high phosphate readings. This includes regularly removing organic debris like leaves and grass clippings and avoiding the use of phosphate-containing cleaners or fertilizers near the pool. Applying a small, weekly maintenance dose of phosphate remover can help sustain a low concentration.