Most people who own swimming pools invariably run up against a central fact of pool life involving the chemistry of their pool's water. The fact is, a swimming pool's water is a delicate balance of disinfectants and pH. For example, there's always a periodic need to adjust a swimming pool's pH levels up or down. Fortunately, a pool's pH can quickly be raised by adding soda ash, though it also needs to be done carefully.
The amount of soda ash (sodium carbonate) to add to a swimming pool will depend on the pool's pH at the time of measurement. For example, if a 20,000 gallon swimming pool has a pH of 7.0 to 7.2, 1 lb. of soda ash will need to be added to the pool. Swimming pool soda ash is an alkaline substance. A swimming pool needs to be slightly alkaline for its disinfectants and other chemicals to work effectively.
Swimming pool pH levels should be between 7.2 and 8, though a pH of 7.4 to 7.6 is best. A swimming pool with a pH below 7 needs to have its pH raised as soon as possible. At pH levels below 7, any available chlorine disinfectant in the pool will disappear, leaving the pool unguarded against bacteria and organic matter. Soda ash in the right amount, which depends on the existing pH level, will quickly raise a swimming pool's pH.
Always measure a swimming pool's pH levels at the same time its chlorine levels are being checked. Checking a pool's chlorine and its pH at the same time will allow both levels to be adjusted, keeping them in sync with each other. If you add soda ash to raise a pool's pH, wait several minutes and remeasure for pH levels. Also, as long as a pool's pH remains between 7.4 and 7.6, there's no need to add more soda ash.
If a pool's pH is below 7, immediately begin adding soda ash at 1.5 lbs. per 20,000 gallons. If a pool's pH exceeds 7.8, though, you'll need to lower it by adding muriatic acid (MA) at 1 qt. per 20,000 gallons. Take care when using MA and follow all package instructions. And maintain a pool's chlorine levels at 2 parts per million. Maintaining proper swimming pool pH and chlorine levels helps keep both levels consistently stable.