Pool Chemistry
Maintaining pool chemistry can seem overwhelming at first but we've broken it down to the most important concepts. Refer to our Chemical Levels table and check below for more information.
Chlorine
Pool water without sanitizer will not only look green and unappealing, it also makes the water a perfect breeding ground for bacteria. The most common method of sanitizing pool water is by using chlorine.
Chlorine tablets (trichloroisocyanuric acid or "trichlor") can be used in a chlorine feeder to maintain an adequate chlorine level over a long period of time. These tablets can be used in chlorine feeders to allow controlled and continuous sanitation.
Calcium Hypochlorite, better known as "shock", is a granulated, chlorine based sanitizer that can be added to the pool water directly to quickly increase the chlorine level. Disperse evenly around the edges of the pool and allow it to circulate through the system.
Whether you have a full chlorine feeder, or you have just "shocked" the pool with calcium hypochlorite, the chlorine level should stay between 1 parts per million to 8 parts per million. If the pool water is reading any less than 1 parts per million or more than 8 parts per million, the pool should be closed until adequate chlorine levels are reached.
Salt
Salt water pools, while not as common as fresh water pools, have become a popular alternative for many people since it eliminates the need for handling or storing harsh chemicals such as trichlor tabs.
Salt water pools stay sanitized by generating chlorine through electrolysis. A special apparatus is installed in the plumbing system that sends an electric current through the salt water which converts the salt to chlorine, the chlorine is then automatically distributed and cycled throughout the water. The chlorine over time will break back down into salt which is then recycled back into the system to be converted back into chlorine again.
However, the salt level in the water won't last forever. Salt can be lost from the water over time from being splashed out. Most chlorine generators will tell you the salt water level and will indicate that more salt is needed.
To add more salt, first consult the owner's manual for the chlorine generator for how much salt to add, depending on the volume of the pool. First, shut off the generator, then add the pool salt directly to the shallow end of the pool. Do not add the salt directly to the skimmer. Let the pump and filter system run for 24 hours to dissolve the salt completely. After the salt has completely dissolved, switch the generator back on and it will start generating more chlorine from the newly salted water.
Just like with normal, fresh water pools, salt will have a chlorine level that must be maintained between 1 parts per million to 8 parts per million. If the pool is reading any less or more than these levels, it must be closed until the right level is reached.
pH Level
pH stands for potential of hydrogen. It is a numeric scale used to specify the acidity or alkalinity (basicity) of a solution.
In swimming pools, the pH level must be between 7.2 and 7.8
Pool water with a low pH level (less than 7.2) is too acidic. This causes problems with maintaining sanitizer levels in the pool, can irritate swimmers and over time can "etch" plaster, due to the corrosive nature of acidic water.
Pool water with a high pH level (more than 7.8) is too basic. Like pool water with a low pH level, water with a high pH level causes problems with maintaining adequate sanitizer levels, as well as irritates swimmers. While it may not be as corrosive, high pH water can cause a white buildup around the edges of the pool known as "scale."
pH levels can be adjusted relatively easily and inexpensively:
- pH levels can be lowered by adding Hydrochloric Acid (Muriatic Acid) directly to the pool water.
- pH levels can be raised by adding Soda Ash (Sodium Bicarbonate) directly to the pool water.
While all pools need some type of sanitizer, it is equally important that their pH levels are maintained as well. This ensures that your sanitizer is as effective as possible, all surfaces in the pool will remain undamaged, and people can swim comfortably.
Total Alkalinity
Total alkalinity or "TA" is the measure of how many alkaline substances there are in the water. TA that is kept at the correct level helps stabilize pH level.
TA should be kept between 60 parts per million to 180 parts per million.
Adjustment of TA is very similar to adjusting pH levels:
- TA can be lowered by adding Hydrochloric Acid (Muriatic Acid) directly to the pool water.
- TA can be raised by adding Soda Ash (Sodium Bicarbonate) directly to the pool water.
Cyanuric Acid
Cyanuric acid or "CYA" is used as a chlorine stabilizer in pools. The right amount can help maintain chlorine levels in water 3 to 5 times longer than water without it.
CYA should be maintained between 30 parts per million to no more than 100 parts per million.