Why is Alkalinity So Important in Pool Water

Why is Alkalinity So Important in Pool Water

What is alkalinity? Alkalinity is the chemical test of pool water to determine that it is in range so that the chlorine in the water can properly disinfect any bacteria in the pool water.

As pool professionals, we are very familiar with the importance of alkalinity in pool water, but it is also essential for wastewater and drinking water treatment. When removing harmful things from the drinking and bathing supply, alkalinity has to be at optimal range in order for the water to be properly disinfected.

If the alkalinity level in water is too low, excess hydrogen remains, causing the pH to drop and reduce the speed of water treatment. This is the same with pool water. If the alkalinity in water is too low, then the PH drops and this slows the speed at which the chlorine disinfects the water.

We recently installed two new heaters.  In both cases, the heaters had been destroyed within two years of their installation, because the alkalinity and the PH were not properly maintained. We see this quite often with pool water that special care is usually taken to maintain the chlorine so that it disinfects the water.   But, the chlorine cannot properly disinfect if the alkalinity and the PH are not also maintained. And, the manufacturers will not replace the unit if the chemicals in the pool have not been properly maintained. (This is the fine line in equipment warranty that you need to always read carefully.)

If the pool alkalinity is not properly maintained and the levels are too high, then this can cause scaling on the pool walls and tile other surfaces.

When the pool alkalinity is not properly maintained, then it affects the PH as well which can result in cloudy water and irritation in the eyes, throat and ears.

Scaling can be corrected and some of the damage reversed but if the water is allowed to stay out of balance for an extended period of time, then this will affect the equipment and surfaces. It can also be corrosive to your pool equipment when not corrected quickly.

If you don’t maintain your alkalinity, you will in time have reduced pool circulation, meaning you could have a clogged filter. If your filter is clogged for just a short period of time, algae can grow quickly in the pool if the water is not being properly filtered.  

Another problem that can come from not maintaining your alkalinity is over time, the pool plaster will develop rough surfaces. Walking on rough surfaces.

It is not possible by just looking at a pool to know if it has low alkalinity. You can only know by testing the water. One of the things about pool alkalinity levels is that it comes down naturally just like chlorine levels in a pool. With PH, you are always lowering the PH, rarely raising it. With alkalinity, you are generally going to be raising it, not lowering it. In order to raise alkalinity, you are going to use a chemical called sodium bicarbonate.

With alkalinity, depending on the temperatures, we keep it at a different level. We don’t maintain the same level throughout the calendar year. Now, if you live in a more tropical climate, then there may be a different practice.

With alkalinity, it is easy to maintain provided you are using a good test kit or strips. When you maintain this part of your pool chemistry, you will prolong the life of your pool equipment and pool plaster and avoid making expensive mistakes in order to bring your pool back in balance.

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