Water Chemistry Guidelines by PoolWaterLAB
To maintain the Pool or Hot Tub yourself, you need to have the following tools
a) If your Pool or Hot Tub with normal water:
1. PooLWaterLAB - Buy here
2. TDS meter with built-in thermometer - Price on Amazon from $10
b) If your Pool or Hot Tub with salt water:
1. PooLWaterLAB - Buy here
2. TDS meter 4 in 1 TDS, EC, Salinity, Temperature - Price on Amazon from $30
* For calcium hypochlorite, lithium hypochlorite, or sodium hypochlorite.
** For sodium dichlor, trichlor, chlorine, gas, BCDMH.
*** Start-up includes the TDS contribution of salt found in chlorine generating systems.
**** Dictated by local codes. Typically 100 pm (mg/L). Some codes are higher, some are lower.
***** Some local codes may dictate a minimum and maximum.
****** when used instead of chlorine
Water Chemistry Adjustment Guide
These commonly accepted chemical parameters do not supersede manufacturers' instructions. Smart phone apps can help calculate associated pool volume and dosage. Chemical amounts have been rounded off for convenience. Always follow the instructions on the manufacturer's label for exact dosage amounts.
• Other calcium hypochlorite products are available from 47% to 78%. Follow the label directions for dosage amounts.
Saturation Index
The Saturation Index (SI) is a method of determining whether water will deposit calcium carbonate or maintain
it in solution. In short it tells you whether your water is corrosive or scale forming. The SI incorporates the five
balance factors: pH, total alkalinity, calcium hardness, temperature, and total dissolved solids. For pool and
spa water, the ideal result of performing this index is to have a result of zero, i.e., SI = O. Balanced water is
between - 0.3 and + 0.3. Corrosive water is - 0.4 and lower. Scaling water is + 0.4 and higher. Having water
outside of the balanced range can contribute to extensive damage to the pool surface, equipment and
structure.
Saturation Index Factors
**High levels of Cyanuric Acid can contribute to false Saturation Index readings. Cyanuric acid should never be above 30 ppm due to the adverse effects on sanitizer activity