If you have not heard of phosphates before this is a basic introduction to them and bottom line is you don’t want them in your pool water.
Phosphates can come from many things like rain water, landscape fertilizer, dust that may have come into contact with landscaping, trees and other landscaping will all have phosphates. One of the effects of phosphates is unwanted algae blooms, because phosphates are an excellent food source for many aquatic plants, like algae. Ideally we want zero phosphates in pool water but over time it’s likely to form some how. There are phosphate test kits for pools that you can get from all pool supply stores and once tested you can see how much phosphates there are in your water and treat as needed with phosphate remover products. Phosphate remover is an expensive product so read the label and only treat accordingly. Once you’ve treated the water with the remover wait a few days or a week to retest to ensure the phosphates have gone down if not then treat again as needed.
The warmer the water and air temps are the more likely you are to get algae blooms and having zero phosphate levels will greatly help to reduce the likely hood of algae forming in your pool.
There are some products on the market like PoolRX that act as a phosphate remover and algaecide in one we recommend the PooRX product full details can found by clicking on PoolRX.
If your pool is experiencing algae blooms here’s some more information