This LSI calculator provides a simple "snap-shot" assessment of pool water balance and is offered "as is" for information and guidance purposes only. Water balance conditions in a pool will change naturally all the time. LSI should be maintained in the range -0.5 to +0.5 which is generally accepted as balanced.

LSI can be increased by taking any one or more of the following actions:

• Increase water temperature
• Increase pH
• Increase Total Alkalinity
• Increase Calcium Hardness

LSI can be reduced by taking any one or more of the following actions:

• Reduce water temperature
• Reduce pH
• Reduce Total Alkalinity
• Reduce Calcium Hardness

So how do you use it...? Enter the water test readings as indicated and click the "Calculate" button. If the resulting LSI displayed is lower than -0.5 or more than +0.5 you will need to adjust the water condition levels (Alkalinity, pH, Calcium Hardness, Temperature etc) so as to bring the LSI to within the range -0.5 to +0.5 (Balanced). By entering different values for each water condition level into the calculator you can determine what combination of water condition levels will provide balanced water in your pool suitable for your pool operating requirements.

Recommended Water Condition Levels:

This calculator assumes that the Total Dissolved Solids (TDS) content of the pool water is circa 500-700 ppm. If TDS increases above 1000 ppm then TDS should be reduced by replacing some or all of the pool water with water with lower TDS (usually by using fresh mains water). We provide no warranty nor do we accept any liability whatsoever either express or implied for any results or guidance displayed by this calculator. Consult a professional pool maintenance technician if you are unsure about any aspect of pool water maintenance or if you require assistance.