Answer: Phosphates are a plant nutrient and contribute to the growth of algae in your pool. City water has phosphates. Fertilizer, ground water run off, plant matter and debris also contain phosphates. Really, the more people who use the pool, the more chance of phosphates from skin cells, shampoo and detergents. We test for phosphates when your chlorine level stays very low. Phosphates can be eliminated, but you have to get ahead of them. After adding the phosphate eliminator, the water can be milky (white sediment), and this may need to be vacuumed up if it is too small for the filter.
We carry commercial grade phosphate eliminator which is very concentrated, so you add less. Our prices are very competitive. Bring in your water for testing anytime.