The Easy Way to Balance Pool Water

Published: 03rd March 2010
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Pool water pH is defined:

Potential Hydrogen (pH) Technically, the pH of pool water or any pH for that matter is a Logarithmic measure or scale of the balance between Hydrogen (H+) and Hydroxide (OH-) ions present in the water. Most of us already know the if the pH is low that water is acidic and conversely if the pH is high the water is basic or alkaline. Therefore, pool water with a pH of 6.0 is slightly acidic water, a pH of 7.0 is neutral and pool water with a pH of 8.0 is basic or alkaline water. For all those up and coming chemists, the equation is: pH= -log10[H3O+]. We do not want to dwell on the chemistry here; however, it is important to understand the point we are making here. As we said, the pH scale is a logarithmic scale. In other words, a pH of 6.0 is 10 times more acidic than a pH of 7.0 and a pH of 5.0 is 100 times more acidic than a pH of 7.0. You just need to be aware that a change in pH from 5.0 to 6.0, which initially seems like a change of only one, is truly a measurement change 10 times stronger.

Simply, pH is the measure of acid vs. base of a solution. Our solution is your pool water. Your objective in balancing your pool water is to find the proper pH level for maximum swimmer comfort and the effectiveness of the sanitizer you are using. First, you really do need to be familiar with the aforementioned pH scale so you may better understand what is happening in the water when you make adjustments. When the pH falls below 7.0 neutral, your pool water becomes acidic. This means your water will become corrosive, aggressive to pipes, vinyl and plaster pool walls, metal components in heaters, pumps and filters. These components can become damaged and become corroded. Low pH water also causes skin and eye irritations, making the eyes look red and cause eye sting. In addition, the pool water sanitizer becomes very active which results in higher effectiveness, but has a rapid depletion rate, so you will use more sanitizer and increase the cost of operation.

High pH can also create problems of its own. When the pH value becomes too high (7.8 and above), the pool water has a tendency to look flat or dull. High pH can also cause skin and eye irritations. When the pH level becomes too high, pool sanitizers become less effective. This greatly reduces the sanitizer activity requiring much more chemical sanitizer to keep the pool water clear and safe.

The pH of the pool water has a great effect on how comfortable the water is for swimmers. Your tears have a pH range of about 7.35 to 7.45. As mentioned above, when the pH strays too far away from this level, pool water becomes increasingly uncomfortable. Red, irritated eyes are an indication that the pH may be out of balance and should be checked and returned to balance.

Considering all of this, you will best meet your objective by keeping the pH between 7.2 and 7.6. This range combines the maximum swimmer comfort with sanitizer effectiveness.


The chemical control and balance of pH is relatively simple. To raise the pH of your swimming pool add pH Increaser (soda ash) to the pool water. So that you are aware, Sodium Bicarbonate does also increase the pH slightly. Do not use sodium bicarbonate (alkalinity increaser) to increase your pH. Sodium bicarbonate is to be used primarily to increase the total carbonate content or total alkalinity of the water. You should always increase and balance the Total Alkalinity first, then adjust the pH using soda ash (Ph Increaser). Soda ash and sodium bicarbonate are the most commonly used water balance products. These chemicals are both safe to add directly into the pool.

The addition of acid such as hydrochloric acid (muriatic acid) or acid salts (sodium bisulfate) lowers the pH in your pool. We recommend using pH Reducer in a granular form because it is effective and safe to handle.

When using pH adjustment chemicals, it is always best to add small amounts of chemicals over time, rather than large amounts at once. We recommend that when lowering the pH or total alkalinity that you do not add more than one quart of muriatic acid or one pound of sodium bisulfate per 10,000 gallons of water per 6-hour period. Recheck the water test and add more chemical if needed.


Total Alkalinity is the measure of the pH buffering capacity of the water's ability to resist a change in the pH. The recommended range is 80-120 ppm. Pool owners must realize that Total Alkalinity (TA) is completely different from alkaline or basic side of the pH scale. They are, however related to one another for proper pH balance.

As mentioned earlier, a desirable pH range is between 7.2 and 7.6. Total Alkalinity plays a major role in stabilizing pH. When TA values are within the proper range, the pH becomes stable. The pH level will remain consistent without much fluctuation. When TA values fall below the recommended range, the pH is easily affected. Even a small amount of high or low pH adjustment chemical introduced into the water can result in large movement or swings in pH values.

Generally, when the Total Alkalinity is low, the pH will remain low too. This causes your pool water to be corrosive and irritating to swimmers. If the Total Alkalinity is high, small concentrations calcium hardness content can produce scale formation. Until the TA is lower, the pH will tend to remain high and treatment to lower the pH will be short lived.

You measure Total Alkalinity with a pool test kit, and for all practical purposes, the test result is equal to the measure of carbonates dissolved in the pool water. To adjust TA, you must adjust the amount of carbonates. To raise TA values, you will need to add Alkalinity Increaser (sodium bicarbonate). Sodium Bicarbonate has a pH of only 8.2 that will raise the TA, but has only a moderate effect on the pH of the water.

To raise the TA level, broadcast Alkalinity Increaser over the pool water surface or you should dissolve it into a bucket of water and pour the mixture evenly around the water edge of the pool.

Lowering TA is a little more involved. You will need either Muriatic Acid or granular pH Reducer. Instead of broadcasting the acid over the pool or around the water edge as for pH adjustment, you must pour the acid in one spot or column at the deep end of the pool. This method causes a different chemical reaction in the water, which will lower the Total Alkalinity, instead of only reducing the pH level.

Lowering TA is a slow process and usually requires repeated additions of acid. We recommend that you do not add more than one quart or one pound of acid per 10,000 gallons of water per 6-hour period.


As a CPO, Certified Pool Operator, with over 22 years experience working in the field of pool and spa care, we have helped thousands of pool owners to resolve their water care issues and to understand pH adjustment methods, total alkalinity and how to accomplish pool water balancing right everytime. For more pool care secrets =>>

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