Understanding Swimming Pool Chemicals

swimming pool chemicals help clarify waterSwimming pools aren’t normally blue, crisp and inviting without just a little help from swimming pool chemicals. We’re all familiar with Chlorine, of course, but if you want to dig a little deeper to get a much broader and clearer picture of practically every chemical used in chlorine pools, here’s your chance.

Please note:

As with all chemicals, you should read the instructions on the individual label to determine the amount to add, how it must be added, a maximum amount that can be added at one time, and other precautions. This article covers basic information, and does not cover specific information pertaining to your individual needs or use in your individual system or for your particular application. Always consult a professional before using any product you are unfamiliar with. It is never recommended to pour or place any chemical in the skimmer.

Here’s the long list. For descriptions and common uses, scroll down.

  • Chlorine
  • Chlorine Alternatives
  • Cyanuric Acid
  • Bromine
  • Ozone
  • Shock
  • Sodium Bisulfate (pH down)
  • Muriatic Acid
  • Sodium Bicarbonate
  • Sodium Carbonate
  • Soda Ash
  • Calcium Chloride (Hardness up)
  • Algistat
  • Algaecide
  • Clarifier
  • Metal Sequestering Agent
  • Enzyme Cleaners
  • Defoamer
  • Filter Cleaners
  • Tile And Vinyl Cleaners

e tabletChlorine-tablet-in-floaterCHLORINE: The most widely-used chemical used to kill bacteria, living organisms, neutralize ammonia, and many other contaminates (such as dirt, debris, and algae spores) that are in pool water. The two most common forms of chlorine are granular chlorine (Dichlor) and chlorine tablets (Trichlor). Chlorine tablets are typically packaged in two sizes: one-inch tablets and three-inch tablets.

CHLORINE ALTERNATIVES: There are numerous alternatives to chlorine. In addition to bromine, some other perhaps not-as-popular alternatives include Bacquacil, mineral systems, chlorine generators (which produce chlorine from salts), iodine, and flourine.

Chlorine and Bromine use are however the dominant primary swimming pool chemicals used in pools today. Although iodine and flourine have been around for some time, their use is much more rare. If your pool uses one of these alternatives, you can get supporting materials for your particular setup from the professional who set your system up. They can and should offer you complete documentation of support material to answer all your questions pertaining to their use.

CYANURIC ACID: Chlorine alone, without help is susceptible to the ultraviolet rays of the sun which can diminish it’s effectiveness literally in a matter of hours. Cyanuric Acid, which is typically packaged and sold as either Stabilizer or Conditioner will help protect chlorine from the sun. Although both granular chlorine and chlorine tablets contain Cyanuric Acid, the amount contained is small, often only a trace.

Therefore, the occasional addition of cyanuric acid is necessary. Cyanuric acid is granular. NOTE: you should not backwash your sand or DE filter for at least 48 hours after adding cyanuric acid. Cyanuric acid is not used with Bromine or any other alternative to chlorine.

BROMINE: An alternative to chlorine used to kill bacteria, living organisms, ammonia, and other contaminates (such as dirt, debris, or algae spores) that are in pool water. Bromine does come in granular form, but by far the most common form of bromine are tablets. Bromine, compared to Chlorine, is more stable but very expensive. Bromine’s niche is with hot tubs and jacuzzis, since it’s very stable in high water temperatures.

OZONE: Ozone is not an alternative to chlorine. Ozone is however, a supplement to be used along with chlorine. Ozone cannot replace chlorine, but when the two are used together, it is an effective cleaning combination. Ozone is also very effective when used with bromine. Although it has a solid place in pool use, ozone’s niche is with spas and hot tubs.

SHOCK: Shocking a pool is mandatory with chlorine, bromine, or any of the alternative chemicals. You will become familiar with shocking your pool. Shock is a granular compound. If you use chlorine, you will want to predominantly use a chlorine-based shock (Calcium Hypochlorite or Lithium Hypochlorite). But, you can supplement your shock schedule with a non-chlorine shock periodically. If you use bromine, you will want to predominantly use a non-chlorine shock (such as Potassium Peroxymonosulfate). But, you can supplement your shock schedule with a chlorine-based shock periodically. If you use an alternative to chlorine (or bromine), then check with a pool professional to assure that you are using the appropriate type of shock. There are no cut and dry rules for how often you should shock your pool. Personally, I shock my pool on an as-needed basis, although some pros say a regular schedule is better.

SODIUM BISULFATE: (pH down): Used to lower pH and Alkalinity. Sodium Bisulfate is typically packaged and sold as “pH Decreaser,” pH Down,” or “pH Minus.” Sodium Bisulfate is granular, and is commonly referred to as “dry acid” (as opposed to the liquid Muriatic Acid, which is an alternative to lowering pH and Alkalinity). Sodium Bisulfate is also used to lower Alkalinity. There is no product I know of that’s packaged as an alkalinity decreaser.

muriatic acid label vintageMURIATIC ACID: This alternative to lowering pH and Alkalinity is more common than you might think. Muriatic acid is a liquid. Be extra careful when handling muriatic acid. It is caustic and well, it’s a strong acid.

SODIUM BICARBONATE (alkalinity up): Used to raise Alkalinity.  Sodium Bicarbonate is typically packaged and sold as “Alkalinity Increaser,” “Alkalinity Up,” or “Alkalinity Plus.” Sodium Bicarbonate is granular.

SODIUM CARBONATE (pH up): Sodium Carbonate is typically packaged and sold as “pH Increaser,” “pH Up,” or “pH Plus.” Sodium Carbonate is granular.

SODA ASH: An alternative for raising pH levels. Like Sodium Carbonate, Soda Ash is also granular.

CALCIUM CHLORIDE (hardness up): Used to raise Hardness levels. Calcium Chloride is typically packaged and sold as “Hardness Increaser,” “Hardness Up,” or “Hardness Plus.” Calcium Chloride is granular.  Note: There is no product that is packaged and sold as a Hardness Decreaser. If your Hardness level is too high, you will have to drain your pool, either partially or completely, in order to lower the Hardness level.

ALGISTAT: Generic name for chemicals used to help prevent algae. Some pool owners use an algistat in conjunction with their other regular chemicals in order to help prevent algae before it can take hold or begin to grow. Algistats are typically packaged and sold as “Preventative Algaecide,” or “Maintenance Algaecide.” Algistats are liquid.

ALGAECIDE: Algaecides are used to help kill algae after it has already begun to grow. The majority of algaecides are liquid, but some types are granular. Once you determine the type of algae (green algae, mustard algae, or black algae), you can purchase the appropriate algaecide and begin treatment. Note: In conjunction with algaecides, you will also need to use a chlorine-based shock and engage in a labor-intensive and time-consuming maintenance schedule to eliminate the algae.

CLARIFIER: An “as-needed” chemical. If water is cloudy, it may be due to thousands of small particles (bacteria, dirt, and other debris) that are suspended in the pool water. These particles are so small that they escape both the chemicals and the filter. If this is the case, a Clarifier is used to restore water clarity. Clarifiers are commonly sold in liquid form and are often used in conjunction with shock to restore water clarity.

METAL SEQUESTERING AGENT: Metal Sequestering Agents can either be liquid or granular and are only used as needed. Metal Sequestering Agents are used to treat color tinted pool water, stains, or the formation of scale. The odd colors, stains, and scale can either result from the minerals that are present in the tap water used to fill the pool or as a result from poor water chemistry. If any of these conditions are present, it can easily be fixed by re-balancing water chemistry and by using a Metal Sequestering Agent, which will rid the water of excess minerals.

ENZYME CLEANER: Enzymes are typically used to break down and eliminate the water line (also called the water ring or scum ring) that is visible just above the surface of the water. Products such as suntan lotions, underarm deodorants, and women’s make-up, as well as body oils and dirt, can attach to the pool wall and cause a water line. Enzymes will react with product residues, body oil, and dirt to break it down and eliminate the water line. Typically, foam will appear after adding an Enzyme cleaner. Foaming signals that the enzymes are reacting with the water line to break it down and are working. Enzymes are a great idea for any pool maintenance schedule.

DEFOAMERS: Defoamers are actually rarely used. They come in liquid form, and as the name indicates, defoamers will eliminate foam from pool water. Foam seems to be found mostly in spas (hot tubs and jacuzzis) because of the rapid mixing of the water and the tiny particles floating around in there. Foam is typically caused by dead skin cells and dead algae but also by sun tanning lotions and other inert particles floating around in your pool.

FILTER CLEANERS: Filter cleaners do not have a direct effect on water chemistry. They do, however, clean the filter, which does have a direct effect on water chemistry. Filter cleaners come in many forms, like in a spray, but are also found in granular form. Make sure you purchase the specified filter cleaner for your type of filter. Note: since filter cleaners are less of a chemical and more of a cleaner, it is okay to pour a filter cleaner in the skimmer.

TILE AND VINYL CLEANERS: A cleaner to clean the walls (and tiles) of concrete, gunite, shotcrete, or fiberglass pools, and to clean liners of vinyl-liner pools. Tile and vinyl cleaners are fairly effective for eliminating light dirt, discolorations or stains and is safe to mix with your pool water. But, if your pool is extremely dirty, discolored or stained, then contract your local pool professionals and pay them to perform a “Drain and Clean”.  Yes, it’s expensive, but a drain and clean should be viewed as more of an investment in the longevity of your pool as opposed to the cost of maintenance.

To learn how to perform regular maintenance on your chlorine pool, check out my article here.

Disclaimer…As with all chemicals, you should read the instructions on the individual label to determine the amount to add, how it must be added, a maximum amount that can be added at one time, and other precautions. This article covers basic information about a variety of swimming pool chemicals, and does not cover specific information pertaining to your individual pool needs or use. Always consult a professional before using any product you are unfamiliar with. Find Local Pool Services Here. Get Up to 4 Quotes. It’s Quick, Free, and Easy!

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