If you just built a swimming pool or purchased a house with one, you may be wondering, "What do I need to keep my swimming pool clean?" In this article, I will explain the basic chemicals needed to maintain your swimming pool. Focus will be on the necessary sanitizer, pH and alkalinity balancers, and filter medium. These three categories are a necessity no matter what pool you may have. As you get accustomed to maintaining your swimming pool, you may want to venture into some other chemicals such as algaecides, clarifiers, metal-outs, etc. If you are new to pool maintenance, it is best to solidify your understanding of the basic chemicals before venturing into some of the more specialized options. (For those of you wanting a quick list of basic chemicals, I will be discussing in this article the need for trichlor tablets or salt, acid, soda bicarb, soda ash, and DE powder, depending on your filter.)
Sanitizer
Every pool uses a chemical of some kind to sanitize the water from any bacteria or germs. The most commonly used sanitizer is chlorine, of which there are many different kinds. We will focus on one of the most popular types in this article, trichlor. Trichlor comes in many different forms. At Berry Pool, we use the tablet form of trichlor for our residential pools. Ideally, if you have a chlorinator installed, the trichlor tablets can simply be placed in the chlorinator until it's full, and the chlorine output can be managed through the dialer attached to the chlorinator. Pool owners who do not have chlorinators installed can purchase floaties which can be filled with trichlor tabs and dispense chlorine unregulated. The ideal range of chlorine levels in a pool is between 3 - 5 parts per million (ppm).
Another common sanitizer is salt; however, it's not so different from chlorine as some may assume. According to Orenda Technologies, "Salt systems are actually chlorine generators, using a process called electrolysis." (n.d., para. 5). In short, salt cells still produce chlorine as a sanitizer. The only difference is, with salt cells, you don't add chlorine tablets to the pool. Instead, in accordance with the instructions in your salt cell manual, you add salt whenever the salt levels in the water are below the recommended range. In addition to maintaining salt levels, you still need to test the chlorine levels. As with a regular chlorinator, salt cells have settings through which you can manage the output of chlorine into the pool.
pH and Alkalinity Balancers
Balancing the pH and alkalinity not only provides a more comfortable swim, but also maximizes the lifespan of your pool equipment and plaster. The ideal range for pH is between 7.4 - 7.6, while the ideal range for alkalinity is 80 - 120 ppm (Pool and Hot Tub Alliance [PHTA], 2022). These ranges should be reflected in whatever water tester you are using. A pH that is too low (acidic) can irritate the eyes and skin of swimmers and deteriorate your plaster, while a pH that is too high (basic) can cause staining on the plaster and clog the filter which can lead to cloudy water (PHTA, 2022). What can make balancing alkalinity and pH tricky is the interconnectedness of the two conditions. If the alkalinity is high or low, your pH will follow, and no matter what you do, you won't be able to correct the pH until you correct the alkalinity. So, what do you use to balance the pH and alkalinity of your pool water?
Muriatic acid is one of the go-to chemicals for lowering both alkalinity and pH. Follow the instructions on the label of whatever acid you purchase to understand how to add in the muriatic acid correctly. First, focus on bringing the alkalinity down to the acceptable range. You may find that correcting the alkalinity will correct the pH at the same time. On the other hand, if your pH is low, remember to first check and address your alkalinity. If your alkalinity is also reading low, then adding soda bicarb to your pool will help raise the alkalinity to acceptable ranges. A rule of thumb is adding 1.4 pounds of soda bicarb for every 10,000 gallons of water to see a 10 ppm increase (PHTA, 2022). If your pH remains low once the alkalinity is balanced, then use soda ash to raise only the pH into its acceptable range (PHTA, 2022).
Filter Medium
There are three main types of filter mediums: diatomaceous earth (DE), sand, or cartridge. The label on your filter should specify what type of filter medium it uses; however, if you need help, reach out to your local pool company for assistance. If you have a cartridge filter, you can stop reading here, because your filter does not take a filter medium. It uses cartridges to filter out bacteria and debris from the water. If you have a sand filter, you won't have to worry about refilling the medium much either. Once a year, or whenever the filter starts to show signs of decreased efficiency, it is recommended to conduct a sand change where you replace the old sand with new sand. The filters that require you to keep some of the media on hand are DE filters. While both sand and DE filters require backwashing (a process where the flow of water is reversed and expels any debris trapped in the filter), DE filters then need to be replenished with new DE. It is recommended to backwash filters at least once a month, so you would be using DE once or twice a month depending how often you choose to backwash.
Conclusion
In conclusion, the chemicals you will want to ensure you have on hand are trichlor tablets or salt, acid, soda bicarb, soda ash, and DE powder, depending on your filter. Chemicals aside from these basic ones can help quickly remedy issues such as algae growth, cloudy water, etc.; however, if they are administered while the water is not properly balanced, they could have adverse effects. As with just about everything, understanding the basics will solve or prevent most, if not all, of your swimming pool issues. If you need extra help with dosing, there are some online calculators that may prove helpful.
References
Orenda Technologies. (n.d.). Salt Pools: The Truth about Salt Generated Chlorine.
Pool and Hot Tube Alliance. (2022). Pool and Spa Operator Handbook. Pool and
Hot Tub Alliance.
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