To lower alkalinity in a pool, the most common and effective method is to add an acid, typically muriatic acid (hydrochloric acid) or sodium bisulfate (a pH reducer). These acids react with the bicarbonate alkalinity in the water, producing carbon dioxide gas that escapes from the pool, thereby reducing alkalinity
Steps to Lower Pool Alkalinity:
- Test your pool water to determine current alkalinity and pH levels.
- Calculate the amount of acid needed based on your pool volume and desired alkalinity reduction (e.g., about 25.6 ounces of full-strength muriatic acid to reduce alkalinity by 10 ppm in 10,000 gallons)
- Add the acid slowly by pouring it into the deepest part of the pool while the pump is running to ensure good circulation
- Run the pool pump for several hours (at least 5 hours) to mix the acid thoroughly.
- Retest alkalinity and pH after treatment and adjust as necessary
How to Lower Alkalinity Without Significantly Lowering pH:
Lowering alkalinity usually lowers pH as well, but you can minimize pH drop by:
- Aerating the pool water after acid addition by increasing surface agitation (e.g., using fountains, waterfalls, or directing return jets towards the surface). Aeration helps expel carbon dioxide, which raises pH without increasing alkalinity
- Partial drain and refill with fresh water to dilute alkalinity without drastically changing pH
- Using selective acidic compounds or mineral treatments designed to lower alkalinity with minimal pH impact (consult professionals)
Summary:
- Add muriatic acid or sodium bisulfate to reduce alkalinity.
- Aerate the pool to raise pH back up after acid treatment.
- Monitor water chemistry frequently to maintain balance.
- For persistent issues, consider partial water replacement or specialized treatments.
This approach ensures effective alkalinity reduction while maintaining safe and comfortable pool water chemistry
