Liquid chlorine does not raise pH. When added to water, liquid chlorine (which has a pH of 13) makes HOCl (hypochlorous acid – the killing form of chlorine) and NaOH (sodium hydroxide), which raises pH. But when the HOCl is degraded by UV, and when used in killing and oxidation, it creates HCl (hydrochloric acid).
Algae can raise the pH. Adding strong liquid chlorine, calcium or lithium hypochlorite chlorine may raise it. Suddenly heating the water, whether from a pool heater or a string of sunny days, could up the pH. Saltwater pools tend to be alkaline.
This, however, is only a slight increase in alkalinity because when chlorine oxidizes or kills, HOCl (strong, killing form of chlorine, hypochlorous acid) becomes HCl (hydrochloric acid, aka muriatic acid) and brings the pH and alkalinity mostly back down.
Using liquid chlorine raises the pH of the water.
When added to water, liquid chlorine (which has a pH of 13) makes HOCl (hypochlorous acid – the killing form of chlorine) and NaOH (sodium hydroxide), which raises pH.
Liquid chlorine and granular shock have a higher concentration of available chlorine than those used in daily chlorination which is needed to kill all living microorganisms, bacteria and contaminants. Both products also are effective for clearing couldy pool water fast and controlling alage.
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.
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.
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.
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.
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.
Effects of a High pH Level
You'll hear complaints about stinging eyes, dry skin, and sticky feeling from the swimmers. You'll notice that the pool has become hazy or cloudy which isn't very appealing to those who want to swim. Chlorine becomes less effective at higher pH levels.
If your pool water pH is above 7.8, add an acid such as muriatic acid or sodium bisulfate. If the pH level is below 7.2, add an alkaline base such as sodium carbonate (soda ash) or sodium bicarbonate (baking soda)
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.
If your pool's chlorine levels are high, it can decrease your pool pH, resulting in acidic water.
Just as you can raise the pH with baking soda, you can lower pool pH with vinegar. It is not, however, the most effective additive for this purpose. You'd have to add so much vinegar, in fact, that it would raise the sugar level of the pool and become food for microbes.
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.
Does baking soda kill algae in pools? Only algaecides can "kill" algae in pool water. However, baking soda can help clear up algae. Use both so you can restore sparkly, clean water!
If you're treating your pool for algae, you'll want the pH to be a little higher than you would typically want, at about 7.8. This will kill the bacteria or algae. Based on your levels, you will either have to lower or raise the pH.
Clear pool water with a green tint may be from pollen, chlorine-resistant algae, or most often from a too-high pH level. When a pool's pH is over 7.8, even high levels of chlorine destabilize and cannot sanitize, and metal in your water and pool components can oxidize, giving off a greenish hue.
Generally, algae grow in pH ranges of 8.2 to 8.7, which is alkaline. Minerals, water, sunlight, and carbon dioxide are other requirements for algal growth.
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.
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.
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.
When chlorine levels are too high, the water's pH will start to decrease, which can eventually lead to corrosion. However, liquid chlorine has a pH of 13 and can cause the water's pH to increase.