Phosphates and Algae Food, Explained
A pool can have perfect chlorine and pH and still grow algae fast, and phosphates are usually why. A higher water table near the coast affects how excavation and dewatering are handled during a gunite pour, which is accounted for in the construction plan rather than treated as a surprise once digging starts.
Algae's Fertilizer
Phosphates enter pool water from fertilizer runoff, decaying leaves, certain tap water sources, and even some pool chemicals themselves. They don't sanitize or harm swimmers directly, but they function as a nutrient source that lets algae grow faster than a given chlorine level can keep up with.
Testing and Reducing Phosphates
A phosphate test kit (separate from a standard chlorine/pH kit) is the only way to know the level; a phosphate remover product can bring it down, but it treats a symptom, keeping yard debris and fertilizer runoff out of the pool in the first place reduces how often that treatment is needed.
Where This Fits
See our Pool Repair service page, or Financing if cost is the next question.
Related Reading
How to Fix Green Pool Water
A step-by-step approach to clearing algae-green pool water, from diagnosis to shock to filtration.
A Weekly Pool Maintenance Calendar
A realistic week-by-week maintenance rhythm for a Houston-area pool that runs year-round.
Chlorine vs. Saltwater Pools: What's Actually Different
Saltwater pools still use chlorine, generated on-site; here is what actually changes in day-to-day maintenance.
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