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Stateside Spas
35815 Clinton St.
Wayne, MI, 48184

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Chemicals Used in Spas and Hot Tubs

Granular Chlorine (Di-chlor) ;

Granular chlorine has been used in spas for many years. Chlorine is a fast acting short-lived chemical when used in hot water. It has 2.5 times the oxidizing potential of Bromine, and can be used as its own shock. When used properly it leaves very little odor in the water. The eye burn and strong smell that many people associate with Chlorine usage is primarily due to a buildup of Chloramines ( a byproduct of Chlorine and organic material) in the water. Chloramines can be removed by regular shock treatments.

Chlorine Tablets (Tri-chlor);

Tri-chlor tablets have a lower pH than granular Chlorine and can lead to equipment damage, if used improperly. Chlorine Tablets is not recommended in hot tubs.

Liquid Chlorine (Sodium Hypo chlorite);

Sodium Hypo chlorite has a very high pH, and when used in a spa can help the formation of calcium scale and make pH maintenance difficult. Liquid Chlorine is not recommended in spas.

Bromine (tablets);

Bromine is a close chemical cousin of Chlorine, and in many ways acts the same. Bromine will tend to build up in a bank in the water that can be reactivated by shocking the water with a chemical like potassium mono per-sulfate, or potassium per-oxy monosulfate. Although Bromine is generally easier on the hair, skin and eyes, more people are prone to being allergic to it than Chlorine, and if water balances are not well maintained while using a bromine floater, the water can be more prone to miss-haps. Like runaway Bromine level, (which can lead to equipment damage), or bacteria growth in the water which can lead to itchy skin or tub rash. Whenever using Bromine it is very important to test your water regularly and make the necessary adjustments.

Scale and Mineral control Chemicals;

Chemical treatment for mineral in your source water is very important. Out of control mineral content can damage many of the components in the spa, and like other avoidable damage, this is usually not covered under warranty. There are many brand names of scale and mineral control chemicals. The majority of them have two components, one is an acid that helps to break up any calcium scale that has started to form. The other component is a polymer that coats the mineral in the water and keeping it from forming scale.


Water's natural state is to be slightly hard. If you add softened water to your spa , the water will tend to draw mineral into itself, through osmosis. Where it finds this mineral, is your heater element and / or your pump seal. You can purchase calcium to harden your water if soft water is all you have available. If you are in doubt as to whether or not your water is hard have it tested, by either a spa and pool dealer, or in some instances of city water, your water company will test your water for you or be able to give you a reasonable estimate of the hardness of your source water. Water drawn from wells can be anywhere from soft to extremely hard. Here again if in doubt, have it tested.

Shock Treatment;

The most common spa / hot tub shock treatment, is Potassium mono-per sulfate, or Potassium per-oxy-mono-sulfate, chemically these two are very similar, in their actions they are almost indistinguishable.

When using Bromine tablets in your spa / hot tub, it is necessary to shock the water with one of these non-chlorine shock treatments once a week.

Clarifying Agents, Clarifiers;

Clarifiers are, for the most part, a polymer, that goes into the water sticks the particles that cause the water to be cloudy together, making larger particles that the filter can more easily pick out. If over used or used with a tub that has an ozone generator, this flocking agent can cause a sticky brownish scum that can be difficult to clean off, so follow the directions, but keep in mind that with polymer based clarifiers less can be more.

Mineral Beds;

In the last few years a new alternative sanitize has come on the market. These are billed as "natural" and contain silver ( a bactericide) and copper (an algaecide). With these systems it is recommended that you use a Potassium based shock or Granular Chlorine as a shock and to activate the mineral bed.

*** SPECIAL NOTE: A growing incidents of pieces of plastic housing from some mineral bed cartridges, getting sucked into the spa / hot tub water pump. This is a non-warranty nuisance, so if you use anything that goes into the filter area of your spa / hot tub be sure that you do not loose a piece down the plumbing, and into the spa / hot tub water pump. Super gluing it together will usually keep it from coming apart in small enough pieces to go down the tube.

Liquid Minerals or Ions;

Coming into fashion are liquid forms of the Mineral based products mentioned above. The same advice and cautions can be applied in the case of these products.

footnote: The use of copper in some of these systems is falling from grace, as EPA regulations regarding the discharge of copper into the water shed get more stringent (Copper kills fish and algae). Silver and now zinc seem to be taking the place of copper for many water treatment programs.

Canada has a ban on many copper based water treatment systems for these reasons.


There are two types of ozone generator used in the spa industry, one is a CD or Corona Discharge, the other is a UV or one that uses an Ultra Violet light to generate ozone from the oxygen contained in regular air.

The way ozone helps purify the water is, when Ozone is introduced to an organic, it oxidizes it, or burns it up. This helps eliminate some of the contaminates you would normally overcome with a disinfectant / oxidizer.

Ozone is the most potent oxidizer that there is gram for gram. That is readily available.

It is not however, the miracle cure it gets sold as. Even with an ozone system it is still necessary to use some chemical sanitizer, as well as pH increaser or decreases, and mineral control chemicals. Ozone will however make your water better behaved and cut back the amounts of other disinfectants needed. Average life expectancy of an ozone bulb is three years. Average warranty on ozone bulbs 1 year.

It is a good idea to check you ozonator frequently to see if it is still working. They will usually have a window through which you can see a purple light, if the light is on the ozonator is working. Note, ozone bulbs can lose potency and should be replaced every 3 years even if they still light.

pH Increaser and Decreaser;

pH increaser is used when the pH of your spa's water drops below 7.2 to 7..4, it can also be used to increase the water's Alkalinity level. Most commonly, pH increaser is sold in a powder form which consists of Sodium Carbonate. Not to be confused with Sodium Bicarbonate (baking soda) which is commonly sold as Alkalinity increaser. Both Sodium Carbonate and Sodium Bicarbonate will increase your pH and Alkalinity, Bicarb will increase the Alkalinity in a higher proportion. Also sold in liquid form as pH increaser is Potassium Carbonate.

pH decrease is used when your tubs water's pH goes above 7.8, it can also be used to lower the Alkalinity level. Sodium Bisulfate is the dry chemical sold as pH decrease. Sodium Bisulfate can also be found in liquid form.

You should always dilute or dissolve pH control chemicals in a pail of water prior to adding it to the spa. Always add chemical to water, not water to chemical, to reduce splash hazard. The chemicals should then be added near the center of the spa with the jets running.

If you add chemicals directly to the spa there is a risk that strong concentrations of chemical will be pulled into the equipment through the suction intakes.