This program uses the Langelier saturation index to balance the water. An index of between -0.3 and 0.3 is correct. Otherwise your water can be corrosive or tend to scaling. This is a very accurate and effective way of balancing water. Simply enter your test results (or use a test strip to do them all in one go), test and print a report. Now with built-in Access database for recording and reporting test results. Includes explanation of Langelier Saturation Index.