Basic Sanitizers

This is the most widely used sanitizer for pool water treatment. It is one of the fastest and least expensive chlorines- fast acting, excellent germicide, algaecide, bactericide, and disinfectant. These are the positive factors. But it also has a high pH (13), a shorter shelf life, and is heavy and bulky. For each gallon we add, we contribute up to 20 ppm TDS. Still, the positive factors outweigh the negative ones for pool water treatment (higher pH, contains caustic soda, and salt). This is not recommended for spas, hot tubs, or smaller pools. In areas with higher pH, TA, and water hardness, I use and recommend, along with the liquid chlorine, a lower pH sanitizer. I use the trichloro tabs in floaters or in automatic chlorinators. This combination of both high and low pH factors sanitizers can help maintain the recommended ranges of pH and TA. Liquid chlorine is not stabilized; if it is used in pools exposed to the ultraviolet rays of sunlight, it may be necessary to add cyanuric acid. In enclosed pools or covered pools with no cyanuric acid in the water, liquid chlorine is more effective as a sanitizer. If surrounded by CYA or higher calcium or TDS concentrations, all chlorine is much less effective than if allowed to be more unstable and react with changes in the pH and TA. This is why we maintain these in the recommended ranges-liquid chlorine 10-12.5% per gallon=available chlorine.

Calcium Hypochlorite
This is available in granular and tablet form. It is also popular sanitizer for pools. It has a high pH (11.8), TDS 9 ppm, contains calcium and can raise calcium hardness, and can leave a visible residue in the pool bottom. In areas with lower calcium hardness, pH, and TA in the water supply, this type of sanitizer should be considered as basic sanitizer, as it can help raise these and make balancing the water easier. It is not recommended for spas and hot tubs, due to the higher pH and higher calcium content: 65% available chlorine, not stabilized. Should be dissolved before adding.

Lithium Hypochlorite
This is granular chlorine with a pH factor of 10.7 and a TDS of 9 ppm. It dissolves instantly and is not stabilized; used effectively as a shock treatment in pools and spas, 35% available chlorine. Safer to store than some other types of dry chlorines. I alternate the use of this with non-chlorine shock and bromine tablets in floaters for spas and hot tubs. With higher pH factor, it helps compensate for low pH factor bromine. Safer for vinyl and fiberglass pools, as it dissolves instantly and does not need dissolving, only in colder water.

Sodium Dichloro
This is stabilized granular chlorine with near neutral pH factor and approximately 56% available chlorine. But I do not fully understand these percentages, as the stabilizer content is over 50%. So we assume that dichloro chlorines are approximately 56% stabilized chlorines. I wish the manufacturers of these would explain this more clearly, but I have been unable to find any answers from my local suppliers or sources. 56% chlorine and 55% stabilizer cannot give the amounts of actual available chlorine. But dichloro, being near neutral and stabilized, is popular as a basic sanitizer for smaller pools, spas, and hot tubs-pH factor is around 6.8 and TDS is 8 ppm. For use in spas and hot tubs, or in pools that are exposed to direct sunlight. Most spas and hot tubs are covered to retain heat and do not need stabilized chlorine, as sunlight is not a factor. I do not sell or recommend stabilized chlorines if they are not needed. In smaller pools that are exposed to sunlight, the dichloro stabilized chlorines can be effective basic sanitizers, and their near-neutral pH factor should be considered. If using any stabilized chlorines, I recommend that you test conditioner levels often, as these can bring the CYA above the recommended ranges. I test my own pool services once each month.

Trichloro
These stabilized chlorines are available in granular and tablet form. They have a low pH factor (below 3) and TDS factor of 10 ppm. The granular form is often used as an algaecide for advanced stages of black algae. Due to the low pH factor, the pump should not run and 48 hours or more are required before swimming is allowed. In most instances, pH and TA must be raised after the trichloro granular is used. Here again, I see a possible controversy as to the exact amounts of available chlorine in trichloro tablets. The container reads: “Active Ingredients: Trichloro-s-Triazintrone=99%; Inert Ingredient= 1%. Available chlorine 99%” but with over 50% stabilizer, where are we as to actual available chlorines? If anyone can give me these answers, please do so. I use trichloro tablets in floaters on my services, along with liquid chlorine. The lower pH of trichloro helps maintain a lower pH. But being stabilized, I test CYA every 30 days. If the CYA is above 80 ppm, I stop using stabilized chlorine and use more liquid or change some water to lower the CYA. Due to low pH and high chlorine in thrichloro tablets; do not add to the skimmer. This can damage plumbing filter and heater and cause stains. This strong corrosive harsh solution can remove the chemicals in plastics that allow pliability and flexibility. Plastics can become brittle and break or become susceptible to damage if exposed to this solution over a period of time.

Gas Chlorine
This is used mostly as a sanitizer for larger municipal pools where a higher, more constant chlorine level must be maintained due to much more traffic. It can also be used in residential pools. Gas chlorine is not stabilized; it has a very low pH of 1.0, and a TDS factor of 20 ppm. It can be dangerous to handle and store, and should be used only by trained professionals. It is much less expensive than other chlorines, but because it is corrosive and possibly dangerous for average pool service professionals to handle, few of us use it.

Bromine
Bromine is a popular and effective sanitizer for spas and hot tubs that are covered most of the time to reduce heat loss and evaporation. Bromine cannot be stabilized with cyanuric acid. If exposed to direct sunlight, the ultraviolet rays can remove bromine rapidly. Bromine can have several advantages over chlorine. It is not dependent on pH, as chlorine is. Combined bromine (bromamines) are effective sanitizers; chloramines are not. Bromine tablets dissolve more slowly than trichloro tablets, and in buffered water bromine has a higher pH. A sodium bromide bank is necessary if changing over to bromine from chlorine. An erosion-type automatic feeder or, in residential spas, bromine floaters, are recommended. Many experts prefer bromine for spas and hot tubs. In buffered balanced water, bromine has a pH of around 7. Trichloro chlorines have lower pH. This can allow an easier pH and total alkalinity range. pH range recommended is 7.5. According to the experts, total alkalinity ranges can vary, but 100-150 ppm TA is most often recommended. pH and total alkalinity ranges often vary according to the pH of the sanitizer used.

Cyanuric Acid
If changing over from chlorine to bromine, and the water has any trace of cyanuric acid (conditioner), all water should be removed and replaced with fresh water. Cyanuric acid disrupts the sanitizing properties of bromine, as bromine tends to attack the cyanuric acid and is less effective as a sanitizer. Maximum conditioner level using bromine is 10 ppm. If bromine-treated water needs chlorine, do not use stabilized chlorines. When chlorine is needed, I prefer the non-stabilized, fast-dissolving lithium hypochlorite. It has a pH factor of 10.7. With bromine around 7, lithium added as needed can help maintain proper pH and total alkalinity ranges.

Potassium Monopersulfate
This is a non-chlorine oxidizer used to remove excessive amounts of nitrogen and ammonia compounds. It also activates bromine from tablets and the sodium bromide bank if it drops below recommended levels. Bromine contains chlorine that allows a continual release of active bromine; but if non-chlorine oxidizers are added, too often they can remove the chlorine residual that is needed to help bromine do its job effectively.

Lithium
My own theory, if using bromine, is to alternate oxidizers every other time bromine is activated. Once use a non-chlorine oxidizer and the next time add the lithium chlorine. This procedure can offer better, safer water with more constant chlorine residual needed to activate the bromine effectively.

Breakpoint Chlorination
If using chlorine only as a basic sanitizer, breakpoint chlorination or super-chlorination must be used to remove the chloramines. Bromine-treated water virtually eliminates this procedure. Bromine absorbs and uses most of the chlorine. Adding lithium and potassium monopersulfate as needed should remove excessive buildups of nitrogen and ammonia compounds, without needed super chlorination. Recommended balance ranges using bromine: ph 7.4-7.6, TA 100-150 ppm, calcium hardness 200-400 ppm, bromine 2-4 ppm. Combined bromine is an effective sanitizer, unlike combined chlorines, and the total bromine residual, not free available, is considered when ppm is maintained.