If the pH gets higher than 7.8, the water is becoming too alkaline. When water is too alkaline, it reduces the effectiveness of chlorine — the pool chemical that kills pathogens. Water with a pH that's too high also can cause skin rashes, cloudy water and scaling on pool equipment.
The chemicals used to sanitize the pool also affect the pH of the water. Granulated or liquid chlorine is alkaline and, therefore, tends to raise the pH level. Bromine is more neutral and has a minimal effect on pH, while chlorine gas is acidic and lowers pH.
As pH goes up, the ability of chlorine to kill germs goes down. Second, a swimmer's body has a pH between 7.2 and 7.8, so if the pool water isn't kept in this range then swimmers will start to feel irritation of their eyes and skin.
Water with a high pH level reduces chlorine's effectiveness. This can lead to other problems like cloudy water and algae buildup.
Extreme pH changes can also affect how the chlorine works in your pool. Chlorine works most efficiently in water with a neutral pH level between 7.4-7.6. If the pool is too alkaline, or more than a pH of 8.0, the efficiency is less than 20 percent.
Aim for a pH level of between 7 and 7.6. If the water pH is higher than 8, anyone who swims in the pool is at risk of skin rashes, while a pH of lower than 7 can sting swimmers' eyes. Some of the many factors that can affect your pool's pH level include heavy rain, the number of swimmers in the pool and chemicals.
Remember that a low pH level is crucial to successfully shocking a pool. At a pH level of 8.0, over half of your shock is ineffective and wasted. At a pH level of 7.2, however, over 90% of your shock will become active algae and bacteria killers.
The most common reason for a consistently high pH level in pools is the use of liquid chlorine or a saltwater system as the primary sanitizer. Sodium hydroxide is produced, which has a pH of around 13. New pool plaster or pebble finishes will also raise pH in pools for about a year after installation.
Baking soda, also known as sodium bicarbonate is naturally alkaline, with a pH of 8. When you add baking soda to your pool water, you will raise both the pH and the alkalinity, improving stability and clarity. Many commercial pool products for raising alkalinity utilize baking soda as their main active ingredient.
However, because chlorine tablets lower pH, it means that your water will not need as much acid to keep the water balanced. This also means that the amount of acid you will need to add to your pool will be reduced. This is one reason why chlorine tablets are ideal if you are going away for a period of time.
Chemicals to Balance pH
Pool professionals use specific chemicals such as dry acid or muriatic acid to reduce the pH level. You can also help maintain pH levels using a product called soda ash. All these chemicals can help maintain the pH level in pools.
Also known as “dry acid”, sodium bisulfate is a fine powder commonly used to lower the pH in pools. Sodium bisulfate is typically preferred over muriatic acid due to its safer use and ease of storage. However, as it is a powder, you should avoid using it on very windy days. The pH level of sodium bisulfate is 1.2-1.3.
What chemicals are used to adjust pH? Sulfuric acid and sodium hydroxide (caustic) are most commonly used for neutralizing acids or bases. Caution must be used for pH adjust applications as an exothermic reaction will occur generating heat.
To bring down pH, use a made-for-pools chemical additive called pH reducer (or pH minus). The main active ingredients in pH reducers are either muriatic acid or sodium bisulfate (also called dry acid). Reducers are readily available at pool supply stores, home improvement centers and online.
After adding pH increaser or decreaser you'll want to wait about two to four hours, although some chemical manufacturers suggest a full turnover cycle, before retesting. The smaller the increments you need to adjust for pH, the less time you'll need to wait for the results to become stable.
Having too much chlorine in your pool water can be dangerous. Exposure to high levels of chlorine can cause lung irritation, skin and eye damage, and provoke asthma. Not only is it bad for your health, but it can be bad for your pool due to the increase in chlorine.
There are quite a few possible causes for your pool to develop an excessive chlorine demand. You might have an infestation of algae, fungus or bacteria that can deplete normal chlorine levels and it is possible for this to occur without many visible signs. Your pool may appear to have a dusty look on the pool bottom.
A good chlorine level is between 1.0 and 4.0 parts per million (ppm), while the pH should be between 7.2 and 7.8. Together, they keep bad bacteria at bay: If pH goes up too high, chlorine's germ-killing power deflates.
According to the Centers for Disease Control and Prevention, the pH level considered to be ideal and safe for swimming ranges from 7.2 to 7.8. This range matches that of our body pH levels, so the water won't cause problems in the body as we swim.
Rainfall dilutes pool chemistry levels and lowers the readings for pH, alkalinity, hardness, stabilizer, and chlorine. Rainfall does not contain chlorine. As well, rainfall brings with it small amounts of contaminants that are washed into the pool.
Most Algae Grows in High-pH Environments
Most types of algae typically enjoy higher pH levels, ranging from 8.2 to 8.7. Once algae starts growing, it can further raise the pH level in your pool and cause more algae growth.
Lowering a pool's pH naturally can be done in four ways: installing a distilled water system to pump in water, cleaning your pool on a regular basis, leaving it alone, and letting the pH level come down on its own as minerals build-up, or installing a pool heater.
The ideal pH level for pool water is 7.4 – 7.6.
To increase pH, add a pH increaser such as sodium carbonate (soda ash)—6 oz. of soda ash raises the pH of a 10,000-gallon pool by 0.2. If your pH fluctuates, the Total Alkalinity might be too low. In that case, add baking soda to increase alkalinity and stabilize the pH.