Calculating Spa and Hot Tub Total Alkalinity

Hot Tub Total Alkalinity or TA is an indication of the level of alkaline substances that are present in the spa water. If your Total Alkalinity reading is too low, the metalwork inside your spa may corrode, your hot tub floor and walls may stain, you may find your water has a green tint, bather's eyes may become sore, and the water may exhibit pH fluctuations, otherwise known as pH bounce.

Please download the relevant Total Alkalinity chart below to determine what adjustments you should make to your water.

How to use the Total Alkalinity adjustment sheets

  1. Print out the correct Total alkalinity sheet.
  2. Use a test strip and read Alkalinity of your swimspa/spa water.
  3. Aim to get Alkalinity to about 100ppm so if your reading is say 160 you will need to reduce your Alkalinity by 60.
  4. Using the Total Alkalinity Adjustment sheet, find your spa/pool type.
  5. Find the reduce line follow it to where it cross the colume 60 and then read the amount and product name.
  6. Measure the correct product amount out and add to your spa or swimspa water with the jets on to allow the product to dissolve.
  7. If your reading is lower than 100ppm then again follow the advice as above but use the increase line on the chart.

Adjusting the total alkalinity of your Pool or Spa

The optimal level for Total Alkalinity in your spa is generally regarded as being 80ppm to 150ppm, although the advice you receive from your dealer may be specific to your spa make and model. Use a total alkalinity or pH increaser chemical to adjust the TA, a little at a time, using the charts above to help you find the right amount to use based on your spa size and adjustment requirements.