Phosphate

Phosphates occur naturally in all of our natural water sources--rivers, lakes, oceans--and they are often present in tap water. In addition, they are contained in other organic matter that finds its way into pools, such as leaves, grass and dirt. Phosphates provide food for the algae that grow in pool or spa water. There are various chemicals on the market that can remove phosphates from the water, helping to prevent algae from becoming established.

Phosphates serve some good in pools. They are commonly used to combat metal staining and scale buildup in pools and hot tubs. Derivatives of phosphates remove metal oxides and scale because they form water-soluble complexes with the metals.

Unfortunately, even a very low level of phosphate can feed algae and create problems in the pool water. In fact, a phosphate level of 250 parts per billion (0.25 ppm) or greater tends to promote the growth of algae. If you can keep the phosphate level down around 100 ppb or less, you can almost guarantee that you will not experience and algae bloom.

The AquaTrend Phosphate Kit has the ability to measure very low levels of phosphates. You sould test for phosphate once a week: the concentration in the water can occur rapidly, due to rain, debris or bather load.