Adjusting the alkalinity of swimming pool water
Alkalinity is a measure of the water’s content of dissolved alkaline salts (carbonates, bicarbonates and hydroxides). Alkalinity acts as a pH buffer and thereby makes the pH value stable. If the alkalinity becomes too high (>150 mg/l), it becomes difficult to change the pH value. Low alkalinity makes it difficult to adjust and maintain the pool’s pH level at the correct level.
Should be measured and adjusted after large amounts of rainfall!
Start by measuring the alkalinity in your water. If you are used to using an ordinary "hand shaker" that shows e.g. chlorine and pH, you should start by using a tester that can also measure alkalinity. You can get test strips that show alkalinity (TA), but they are not very accurate.
We recommend using a SmartTester from Lovibond (also known as the 2nd gen of Scuba II) - it gives you a good measurement result. note that if its measurements are above or below the working range it is designed for, it simply shows "hi" for high or "lo" for low. You can ALWAYS trust the SmartTester result
High alkalinity:
Too high alkalinity makes it difficult to change the pH in the water. The water may become cloudy/hazy and “bubble”. If the alkalinity is > 150 mg/l, it must be lowered:
- First, the PUMP must be turned off!!
- Dissolve 1.2 kg Saniklar pH-Minus in a bucket of pool water (approx. 0.5 liters) to a light slurry and add it to the deepest end of the pool.
- This will lower the alkalinity by approx. 20 mg/l in a 25 m³ pool and wait approx. 30 minutes.
- Test the alkalinity again and repeat the 2 points above until an alkalinity between 80-120 mg/l is measured.
If, for example, you have a 40 m3 pool and measure an alkalinity of 200, you should "aim" to reach an alkalinity of 100. In that case, you must use 5 x 1.2 kg per 25 m3 - or ((5x1.2)/25)*40 = 9.6 kg
Low alkalinity:
After heavy rainfall in an outdoor pool without a cover, the alkalinity will often drop sharply and in some situations may disappear completely. At the same time, the pH becomes uncontrollable and very difficult to adjust. If alkalinity is <50 mg/l, add Saniklar Alka Plus
- Measure the water’s alkalinity with an alkalinity tester and adjust if necessary to a level of 80 - 120 mg/l.
- To raise the alkalinity by 10 mg/l in 20 m³ of water, add 350 g Alka Plus = 2½ dl.
You can enter your measurements in our calculator, which you will find under the Saniklar Alka Plus product
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