PH is a measure of the acidity or alkalinity of water. Maintaining proper pH levels in your hot tub is critical for protection of your spa surfaces, bather comfort and for the ability for most hot tub sanitizers to work at their best. The pH Scale is logarithmic and measures of 0.0 to 14.0 with 7 being neutral. The recommended pH level to be maintained in your hot tub is between 7.4 and 7.6. Measurements below 7.4 show that your hot tub water is more acidic than it should be. This can corrode spa surfaces, plumbing and equipment and can cause skin irritation and red eyes. Measurements above 7.6 show that your hot tub water is more base or alkaline. High pH can cause the sanitizer to lose some effectiveness; minerals can fall out of solution, causing cloudy water, scale buildup, and equipment and surface damage.
Many factors can affect your hot tubs pH level. This includes airborne contaminants, rain, fill water and bathers. Some chemical products can also affect the pH like sanitizers, shock treatments and balancing products. Since the pH changes frequently due to these and other outside factors it is recommended to test the pH level at least twice a week. When testing if your hot tubs pH level is not between 7.4 and 7.6, it is time to make an adjustment. If your pH measured high we need to lower it. To lower your pH use a product such as SpaPure pH Down or ProTeam Liquid pH Down. If your pH measured low we need to raise it, to raise your pH a product such as SpaPure pH UP or ProTeam Spa Liquid pH UP should be used.
If you are adding pH UP and your pH is not responding by rising, check the total alkalinity. If the total alkalinity is high and increasing, the problem could be bicarbonate scale. This becomes an issue when your hot tub water is not allowed to gas off properly. Trapped gases are reabsorbed into the hot tub water and can drive down pH and the total alkalinity up. This can also cause cloudy water. You may need to leave your hot tub cover off for a few hours to a few days to help fix the problem.
Is it really a big deal if your PH reads a little high like 7.8 or a little low like 7.6? As mentioned before, the pH scale is logarithmic. This means there is a ten difference between each successive full number on the scale. A pH reading of 6.0 means a tenfold increase of acidic molecules over a 7.0 reading. The difference between 6.0 and 8.0 is a 100 times greater (10 x 10). That being said you should try to maintain the pH between 7.4 and 7.6 all the time for optimum water quality.