Alternative Sanitizers

A group of products that sanitize pool, spa and hot tub water, by means other than the application of chemicals to the water. Includes such products as: salt chlorine generators, ultraviolet sanitizing systems, mineral purifiers, ionizers and ozonators.

Balanced Water

Pool or spa water that is within the accepted water analysis parameters for: pH, sanitizer, total alkalinity, calcium hardness, chlorine stabilizer (chlorine pools only) and minerals. The balancing, of the pool or spa water, helps to eliminate water chemistry problems.


The generic name for a non-chlorine, non-bromine, sanitizer that utilizes the polymer PHMB (polyhexamethylene biguanide). It is used to totally eliminate the use of chlorine or bromine. A popular non-halogen, alternative pool, spa or hot tub chemical sanitizer. Chlorine, bromine or non-chlorine shock will destroy the biguanide polymer.


A slippery coating of microorganisms that can develop in poorly sanitized pools and spas.


Feeding devices used to introduce bromine into pools or spas. Most automatic types can be plumbed inline. Others are simple floating varieties. All are intended to make the application of bromine easier and more consistent. Do not use chlorine in place of bromine, in any brominator.


Closely related to chlorine in chemistry. It has become popular, especially in spas, because it has much less odor than does chlorine. Available in solid forms for use in specialized bromine feeders or dispensers. Also, available as a 2-part product for use in spas and hot tubs.


Chemicals that help to stabilize the pH. In pools and spas, sodium bicarbonate (baking soda) is typically used to create a buffer that helps keep the pH in the optimum range.

Calcium Carbonate

Crystalline deposits (scale) that can form on all under water surfaces, if the water is excessively high in calcium hardness. High pH and high total alkalinity can worsen the problem. Responsible for cloudy water conditions that may result due to pool or spa water being out of balance.

Calcium Chloride

A calcium compound that is used to raise the calcium hardness of the water. Typically, available in a granular form for use in pools and a liquid form for use in spas and hot tubs. Used to raise the calcium hardness level, of soft pool or spa water, into the 150-200 PPM range.

Calcium Hardness

A measurement of the dissolved calcium content of the water. Can be tested by various methods and is reported as PPM of calcium carbonate. Proper pool or spa water balance usually requires that the calcium hardness of soft water be raised to 150-200 PPM. Higher levels can lead to scaling or cloudy water problems and may require chemical treatment.

Cartridge Filter

A type of filter that utilizes a porous, pleated component or bag to remove particles.


Irritating, odorous forms of combined chlorine, formed by the reaction of chlorine with nitrogen containing waste products. Ineffective as a pool or spa sanitizer. High levels of chloramines can cause the problems of “Red Eyes” or “Stinging Eyes.” Usually requires a shock treatment to lower or destroy the combined chlorine level.


Feeding devices used to introduce chlorine into pools and spas. Most automatic types can be plumbed inline. Others are simple floating varieties. All are intended to make the application of chlorine easier and more consistent. DO NOT USE BROMINE IN A CHLORINATOR – USE ONLY IN AN APPROVED BROMINE FEEDER. Only solid trichlor products (tablets, sticks or other shapes) should be used in a chlorinator.

Chlorine, Available

A somewhat archaic term for describing the chlorine level. Sometimes used as “Free Available Chlorine” or “Total Available Chlorine.”

Chlorine, Combined

That form of chlorine that has reacted with nitrogen containing waste products. Chloramines are the major constituent. Ideally, the combined chlorine should be no more than 1 PPM, as high levels can cause odor and irritation problems.

Chlorine Demand

A measurement of the amount of Free Chlorine that must be added to water, showing a zero Free Chlorine level, in order to produce at least a minimally positive Free Chlorine level. The test can be performed by some dealers.

Chlorine, Free

The active, germicidal form, known chemically as hypochlorous acid. This is the preferred form of chlorine sanitizer used in pools and spas. Tested by DPD, Test Strips and Syringaldezine and reported as PPM. A level of 1-3 PPM is considered ideal. Higher levels can cause vinyl liner fading problems and bather irritation.

Chlorine Lock

A somewhat archaic term used to describe the presence of high levels of combined chlorine. Combined chlorine is the difference between the Total Chlorine reading and the Free Chlorine reading. Ideally, it should be less that 1 PPM. High combined chlorine content can result from the presence of nitrogen containing wastes such as urine and sweat. Many people view any situation as chlorine lock, where lots of Chlorine has been added and there is little improvement in the chlorine readings. This is not chlorine lock, but simply a case of needing to add more because of the pool’s high demand for chlorine.

Chlorine Neutralizer

A chemical used to quickly lower the chlorine level of a pool, spa or hot tub. Typically, only in the case of a serious overdosing of the water. It is always better to add product incrementally: you can always add more – you can’t take out!!! Can be used with bromine as well. Typically, sodium thiosulfate or sodium sulfite is used in this application.

Chlorine, Total

The measurement of the total amount of FREE CHLORINE plus the amount of COMBINED CHLORINE. Tested by OTO as well as the materials used to test for Free Chlorine. Reported as PPM. Test readings are always higher than the Free Chlorine readings. Ideally, the Total Chlorine level should not be more than 1 PPM higher than the Free Chlorine reading.


A class of polymer based products that act on suspended, insoluble particles and organic debris and coagulate or clump them together, for easier and more efficient filtration. Some particles, especially dead algae, might otherwise pass right through some filters. Used in conjunction with proper pool or spa water chemistry and sanitizer levels, these products help produce sparkling, crystal clear water and help eliminate water clarity problems.

Corona Discharge

A method for producing ozone, by utilizing high voltage arcing to convert oxygen (O2) into ozone (O2). Refer to the listing for Ozone for more information.

Covers, Solar

A cover used to help increase or maintain the water temperature. Typically, a plastic, bubble-filled material that floats on the pool surface. Cannot be used for winterizing or safety purposes.

Degassing Unit

A mixing chamber for ozone and water, that can be used to increase the efficiency of an ozonator. By creating small bubbles of ozone, contact time and absorption is increased and the amount of ozone “gassing off” is decreased.


Can result in pools that have used quaternary ammonium compound (QUATS) algaecides. This can be made worse, if there is an air leak in the return line. In spas, body oils can react with the natural alkalinity of the water and form “soaps”. Aeration will increase the foaming problem. Anti-Foam products and enzyme products are useful in controlling the problem.


The process by which insoluble, fine particles are caused to precipitate from suspension. Alum works by this principle. However, other more modern polymer-type liquids or tablets accomplish the same net result, without having to generate large amounts of additional gelatinous precipitate.


A rash-like bacterial infection of the hair follicles caused by inadequate sanitation of spa or hot tub water. Caused by the same bacteria, pseudomonas aeruginosa, responsible for swimmer’s ear and conjunctivitis. Medical treatment should be sought in suspected cases.


Ground Fault Interrupter. A type of electrical safety receptacle that prevents the possibility of electrical shock in outdoor equipment or around water. Usually, if not always, required by local or national codes.

Heavy Metals

A term used to describe the presence of metallic elements such as iron, copper, manganese, etc. Responsible for many types of problems involving staining and colored pool or spa water.

Hot Tub

Originally designed and manufactured along the line of a barrel, these products are an alternative to the typical spa. Most are made of redwood or cedar and can have an internal vinyl liner to keep the water away from the wood. Equipped with heaters, air jets and filters, hot tubs provide relaxing baths, arthritis relief and enjoyment. Sizes can vary. The term “hot tub” is used, somewhat, interchangeably with the term “spa.”


A mineral, which can occur naturally in water and can be especially high in well water. Can lead to problems with staining and discoloration of the pool or spa water and underwater surfaces. Requires treatment with chelating agents. Best to treat prior to adding chlorine or raising the pH. Testing of the water will determine the concentration in PPM and allow for an appropriate dosage of chelating agents to be added. Any measurable amount of iron is capable of causing a problem, if not treated.

Mineral Purifier

A type of device that releases copper, silver or zinc ions into the water at very low levels. In this ionic state, these minerals can function in the sanitizer role and help control algae and bacteria in pool and spa water. Mineral Purifiers work on the principle of erosion and do not require electrical components. Most include some type of replaceable cartridge that contains the copper, silver or zinc materials.


Mono persulfate shock. Refer to the listing for non-chlorine shock.

Non-Chlorine Shock (MPS)

Typically potassium monopersulfate. Also known as monopersulfate compound and potassium peroxymonosulfate. Replaces or assists chlorine in destroying organic contamination and chloramines. Used as a shock treatment, it is completely soluble, chlorine-free, quick acting and does not create a build-up problem.

Ozone (O3)

Typically produced by an Ozonator installed in a pool or spa. Ozone (O3) is a form of oxygen (O2) and is a powerful oxidizing agent. It is used to destroy organic waste and byproducts and help in the control of algae and bacteria. Not a stand-alone sanitizer: needs some supplementing with chlorine, bromine or ionization. Ozone is produced by a UV (ultraviolet) light source or by electrical arcing (corona discharge).


The pH scale goes from 0 to 14. 0 is the most acidic. 14 is the most alkaline. 7 is neutral. The ideal range for most pools and spas is 7.2-7.8. This is a compromise of several factors: allows for reasonable effectiveness of chlorine or bromine, bather comfort, corrosion and scaling considerations and the solubility of dissolved minerals. pH values less than ideal can lead to corrosion problems. Values higher than ideal can lead to cloudy water and scale formation. pH is an important parameter and must be controlled. Chemicals are available to lower or raise the pH. Control of total alkalinity aids in stabilizing the pH.

Potassium Monopersulfate

A chemical name for Non-Chlorine Shock. Refer to that listing.


Parts per million. Used as a unit or measurement of concentration, for most common pool water parameters and chemicals. 1 PPM equals 1 pound per 1 million pounds of water. pH is the only common pool parameter not expressed as PPM. Occasionally, concentration is expressed in grains: 1 grain = 17 PPM.


Tthe formation of an insoluble chemical compound, thereby, causing it to drop out of solution. Changes in the water analysis parameters of pH, total alkalinity and calcium hardness can cause precipitation. Not treating dissolved minerals such as iron, can lead to precipitation that can result in staining and discoloration problems. Precipitation of calcium can lead to cloudy/hazy pool or spa water or scale deposit problems on the underwater surfaces.

Pseudomonas Aeruginosa

Infectious, pathogenic bacteria. Inadequate sanitation, gross contamination or poor water management can foster the growth of this bacterium, causing swimmer’s ear, conjunctivitis or folliculitis. Treatment should include proper medical services.


Chemicals or equipment used to kill bacteria, viruses, algae and mold. Include: chlorine, bromine, biguanide, ozone, ionization, mineral purifiers, salt chlorine generators, ultraviolet (UV) sanitizing, etc.

Scale Formation

Caused when the levels of dissolved calcium carbonate reach the maximum, based upon the actual water chemistry. Scale (calcium carbonate precipitate) shows up as a whitish coating on the underwater surfaces. If left untreated, it can cause problems with filtration and pool heating. Scale can occur, if the calcium hardness exceeds 400 PPM and the pool chemistry is not properly maintained. Scale can be controlled by lowering the calcium hardness level, adding Scale Control Chemicals (sequestering or chelating agents), lowering the pH towards 7.2 and lowering the total alkalinity towards 80 PPM. Pools, with scale-forming potential, should avoid the further use of products such as calcium hypochlorite: a source of calcium.


Used in Ionization units. Silver ions can function as a bactericide.

Sodium Bromide

Converts into active bromine sanitizer, when oxidized by the action of chlorine or non chlorine, monopersulfate shock. Typically, used to treat a variety of resistant or problematic conditions such as “pink” algae, water mold, slimes and yellow-mustard algae

Sodium Bisulfate

Available as a pH reducer, this acidic, granular chemical is used to lower the pH and/or total alkalinity. Neutralizes the effects of high pH chemicals. Also known as sodium hydrogen sulfate. Concentrated solutions are very acidic!!!

Sodium Dichlor

A form of stabilized chlorine. This chlorinated cyanuric acid is completely soluble and is essentially pH neutral. Used for routine daily sanitizing and shocking (superchlorination) in pools and spas. Typically, 56% available chlorine.


A popular form of aquatic recreation. Available in a range of sizes and shapes, these products are used for relaxing bathing, arthritis relief and fun!!! Portable, ready to plug in and in ground, built-in variations are available. Units feature heated water, air jets and massage therapy. Hot tubs are a design variation, usually of wooden construction. The phrase “hot tub” is sometimes used interchangeably with that of the term “spa.”

Total Alkalinity (TA)

A measurement of the ability of the water to resist changes in pH. Water with a TA of 80-120 PPM is sufficiently buffered, so as to resist rapid changes in pH. This makes pH management easier. Additions of sodium bicarbonate are used to raise the total alkalinity: 1.5 pounds will raise the TA, of 10,000 gallons, by approximately 10 PPM. High TA can be lowered by the addition of muriatic acid or dry acid (sodium bisulfate).

Ultraviolet (UV)

UV Sanitizing Systems can be, plumbed in-line, and used to reduce the overall population micro-organisms, as the water passes through the unit. There is no residual effect of the UV, so backup sanitizing is highly recommended. UV is also used in some Ozonators (refer to the listing for Ozone), in order to convert oxygen (O2) into ozone (O3). Because UV rays from the Sun can destroy chlorine or bromine, cyanuric acid conditioner/stabilizer is used to minimize the negative effect, of sunlight, on the chlorine concentration.

Water Chemistry

In order to minimize the possibility of pool or spa water problems and to maximize the bathing pleasure, it is important to maintain or balance the common pool water parameters, within the suggested optimum ranges. These parameters include: sanitizer level, pH, total alkalinity, calcium hardness, chlorine stabilizer (outdoor chlorine pools only) and the control phosphates, nitrates and trace heavy metals. Not all of these parameters are problematic: a lot depends upon the nature and quality of the source water.

Water Quality

Refers to the state of the overall pool or spa water conditions, regarding such factors as: sanitation, water chemistry, water clarity, water color and the appearance of the underwater surfaces. Water quality can become an issue in a variety of pool or spa problems that detract from the goal of sparkling, crystal clear pool or spa water.

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