Algae Problems

Water Balance/Saturation Index Factor

Temperature + Total Alkalinity + pH + Calcium Hardness + Stabilizer Adjustment + TDS = Saturation Index

Simply put, proper Water Balance means keeping ALL chemicals in the right amounts. The following 6 factors affect water balance: Temperature, Total Alkalinity, PH, Calcium Hardness, Stabilizer and Saturation Index. It is possible to have Temperature, Total Alkalinity, pH, Calcium Hardness and Stabilizer in the proper (ideal) range and still have unbalanced water because the Saturation Index may be too high or low.

2 Goals of Water Balance:

Protect Swimmers from Irritating or Unsafe Water
Protect Equipment from Corrosion or Scaling

The Saturation Index (also referred to as the Langelier Index) is a major health indicator of your pool because it determines whether the water is damaging the pool surface and equipment.
Water that is UNDER-saturated (Low saturation index) is aggressive, hungry and corrosive. In this state the water may cause etching, pitting, dissolving and staining of walls, grouting and plumbing.
Water that is Saturated (Zero saturation index) is in equilibrium, balanced and neutral to pool surfaces and equipment. In this state the water has no effect on the pool or equipment.
Water that is OVER-saturated (High saturation index) is scale forming. In this state the water will deposit excess minerals on the pool and equipment in the form of scale.
Since Calcium is the most abundant mineral in pools, it is the most likely mineral to be dissolved by corrosive Under-saturated water. Calcium is also the most likely mineral to be deposited on pool equipment in the form of scale from Over-saturated water.
Water that is only slightly scale forming is recommended. Ideally a very thin residue of calcium should form on pool surfaces.
The best way to see the relationship between various factors and the Saturation Index is to move the Perfect Pool and Spa Software! sliders around and watch the Saturation Index change with each factor.
The Perfect range for the Saturation Index is 0 to 0.5 (slightly scaling).

Effect of individual factors on Saturation Index:

As Temperature Increases SI Increases
As Total Alkalinity Increases SI Increases
As pH Increases, SI Increases
As Calcium Hardness Increases, SI Increases
As Stabilizer Increases, SI Decreases
As Total Dissolved Solids Increase, SI Decreases

Perfect Pool and Spa Software! Users: Test water and input all results into the main screen. Follow recommendations for exact amounts, when and in what order.