When learning how to balance the water in your hot tub, you must first understand the basics. Optimum water balance is crucial as as it affects the appearance and safety of the water and equipment; pH is most critical, but the TA and CH levels must also be considered. There are five factors that affect the chemistry of your water; although they may sound like a bit of a science experiment, with the right tools and knowledge, they’re pretty simple to master.

The Rule of Five:

  • pH
  • Total Alkalinity (TA)
  • Calcium Hardness (CH)
  • Temperature
  • Total Dissolved Solids (TDS)


pH is measured on a scale of 0-14; 0 being the most acidic, 14 being the most alkaline, and 7 being neutral. The recommended pH range for a pool or hot tub is between 7.4 and 7.8.To maintain the perfect pH balance we recommend: Spa Life pH Up to raise pH andSpa Life pH Minus to lower pH. Please use as directed.

Total Alkalinity

Total Alkalinity is a measure of the amount of alkaline salts in your water, it’s important as is acts as a buffer to control changes in the pH. Always maintain TA between 100-150 ppm as it’s crucial to the protection of your hot tub equipment. We recommend Spa Life Buffer – a dose of four level tablespoon will raise the TA 20 ppm in 2400 litres of water.

Calcium Hardness

Calcium Hardness is a measure of the amount of calcium that is present in water. Low CH can lead to corrosion; high CH to scaling, cloudy water and staining. Maintaining the CH between 150-300 ppm will prevent a variety of unwanted water conditions. We recommend: Spa Life Cal – 10 level tablespoons will raise CH 50 ppm in 2000 litres of water. To lower CH, drain some of the old water out of the tub and refill with fresh tap water, and remember to retest.


The suggested temperature range of your hot tub should sit at approximately 102-104 degrees F or 38-40 degrees C. Maintaining the right temperature can affect how quickly your sanitizer is consumed and dissolved.

Total Dissolved Solids

Total Dissolved Solids is a measure of how saturated the water has become from use. The TDS level should remain below 1500 parts per million (ppm). Once it reaches the 1500ppm mark, it’s time to drain and fill your tub!