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Spa and Hot Tub Service -  Spa Water  Chemistry

Just like the first time driving a car -  especially if it was a stick shift, spa and hot tub care and water chemistry can seem a bit confusing, at first, but with a little practice, and a firm grip of the concept, pretty soon, it just becomes second nature. 

This page, entitled Spa Chemical Basics,  is a recap and continuation from the 's home page.

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There are 4 major components to spa water care:  Sanitation, Corrosiveness, Cleanliness, and  Clarity.  Only if the spa water is in proper chemical balance, and properly sanitized, can the the filtration system effectively take care of the other two.  While there a lot of possible complications to spa chemistry, the average homeowner just needs to know the basics - the rest can be learned on a "need to know" basis.  We'll cover those basics of spa chemistry here, and A-Pro Services  will be happy to help with all the rest.

The Basics of Spas and Hot Tub Chemistry


Chlorine and other Halogens - Still the most widely used, and, when used properly, the most  over all cost efficient, chlorine and bromine have been used as effective sanitizers in spas and hot tubs ever since the need for water sanitation was understood. A properly sanitized spa should not have a strong chemical odor,  nor should it burn the eyes. 

Spa water chemistry is very similar to pool chemistry, with some notable considerations. First there is the water temperature.  Since spas are usually much warmer than pools, chemical imbalances are more critical, and more noticeable.   Spas and hot tubs are usually covered, to hold in the heat, so poorly managed chemistry usually makes itself known as soon as the cover is opened.   There is also a higher ratio of bodies per gallon of water in a spa, so chemicals tend to fluctuate more quickly.  Also, spa jets are used more closely to the body, and can penetrate the skin.  Because of this, some people become sensitive to chlorine and bromine, especially if the sanitizer level is too high.

Bromine has long been the standard sanitizer in spas and hot tubs, because it is milder and less acidic than chlorine.  Most modern spas have a built in means of dispensing bromine, even if it is only to put a tablet or two in the skimmer basket. Bromine tablets are buffered to be less corrosive than chlorine tablets, and are preferred with most dispensers.  Chlorine is still often used in powder form, and put directly into the water with the jets on high speed, so that it is dissolved quickly.

 One of the most important things to do in order to keep the spa sanitized, without a strong chemical odor, is to shock the spa regularly, an leave the cover off for several hours after doing so.  As chlorine and bromine work, they build up in the water in the form of combined, or used sanitizers.  Shocking with a non chlorine shock oxidizes -that is, burns off- these contaminates, and leaving the lid off gives the resultant gases a way to escape.  The result is that now all of the sanitizer in the spa is "free and available" to kill contaminates, and leave the water smelling fresh.

Other Sanitizers

In order to lower the amount of sanitizer needed, most modern spas are equipped with ozone generators.  Ozone generators keep the spa constantly purified while the low speed is running, and, since the water is constantly oxidized, less sanitizer is needed.  Concentrated ozone is unhealthy to breathe, so the ozone generator is turned off when any function other than the low speed pump is running. Spas that use ozone have a somewhat sweet smell,  like the smell in the air after a lightning storm.  Ozone is an effective sanitizer for quick kills, but has no residual killing power.  Ozone generators are very effective in closed systems and is almost a standard feature in modern spas,  They are also used in many public water supplies.  Because of the short lifespan of ozone before it reverts back to oxygen, it is recommended that other, more stable sanitizers must be used along with ozone. 

Copper has been used for many years in swimming pools as an effective algaecide, and as of late, is sold as the primary chemical in such products as Pristine Blue.  Because copper is such an effective algaecide, it prevents the growth of many organics. Periodically, a halogen, like chlorine, or, more specifically, sodium dichloro-s-triazinetrione dihydrate (dichlor) is used to oxidize the free copper, and establish a low level of free chlorine. Over usage of copper, combined with Chlorine, can cause staining, so, as with any chemical. be sure to follow the manufacturer's directions!

Silver is used in such products as Nature 2. Silver oxidation systems are similar to copper systems, in how they work, and usually use non chlorine shock, or monopersulfates to oxidize the silver. Silver systems are usually sold in the form of a  stick, or cartridge, which is placed inside the filter.  The non-chlorine shock is used to oxidize the silver, and is applied either before or after each use. Some people find it less convenient, but it does have a sustained residual, so it can be a viable alternative to other sanitizers for those who are sensitive to chlorine and bromine.  Usually, it is used as a supplementOver usage of both copper and silver  can lead to staining, so you should never use more than the manufacturer recommended amounts of these chemicals.

Biguanide is used in products such as Baqua Spa  and is only an effective sanitizer against bacteria. You must also apply weekly algaecide and shock treatments. Recommended range of 30 to 50 ppm. Biguanide systems use hydrogen peroxide as a shock chemical; follow the directions of your dealer or manufacturer.  Be sure to make the shock and algaecide treatments on a routine basis.

Salt Systems, have become more popular in recent years, as an alternative to directly adding chlorine or bromine.  Salt, chemically, is sodium chloride. Salt is added directly to the spa, until the proper level is reached, around 2800 parts per million.  Salt systems use an electronic device to separate the chlorine from from the sodium, and use that chlorine as a sanitizer.  The sodium then becomes sodium hydroxide which later recombines with the chlorine to reform salt. This is a continuous process, and, as long as the filtration system is on and the unit is in working order, the spa water remains treated.  Salt systems do not work when there is no circulation, so adjustments must be made if the spa pump is on a timer.  The better salt systems have either manual or automatic methods for super chlorination,  or "shocking" the spa.  Once adjustments are made, salt systems are usually trouble free for several years with only minor maintenance.  as with other sanitation methods, the pH, Total Alkalinity, and other corrosion factors must still be maintained independently from the sanitizer.  Salt systems are becoming more popular, because the sanitizer is less noticeable.

Corrosiveness - Total Alkalinity, pH, and other Spa Water Chemistry Factors

Corrosion or scaling conditions in the water are determined by considering several factors.  Total Alkalinity   also known as Base is, to put it simply, a measure of the water's ability to neutralize acid.  Potential Hydrogen, or pH, is a measurement of the relative acidity of the spa water at a given time.  If the total alkalinity is low, the water is less able to neutralize acid, and therefore, the pH tends to drop.  Likewise, if the total alkalinity is high, the pH tends to rise. The base demand is a calculation of the total alkalinity needed to keep the pH  stable.  The Langlier Index, or water gram,  takes into account the total alkalinity, calcium hardness (or Total Hardness) level, and water temperature to determine the pH of saturation.  This is compared to the observed pH, to determine whether the water is corrosive, or scaling. While this all may sound complicated, it really is more than the average spa owner needs to know. 

Normally, the Ideal ranges are:  pH: 7.2 - 7.8, with 7.4 being ideal.  Total Alkalinity:  80-120.  Total Hardness:  150-250.  The exact ideal levels vary, but should fall within these ranges.  note that it is high calcium levels in the pool water which tend to cause scale buildup on surfaces, in equipment, and plumbing.

When making adjustments, since the pH is stabilized by the Total Alkalinity, you should always adjust the total alkalinity before attempting to adjust the pH.  Total Alkalinity and pH are lowered by using  dry acid like sodium bisulfate, which is often sold as "pH lower" or a similar name.  Acids should be well dissolved in water before adding to the spa. To raise the pH, sodium carbonate, or Soda Ash is used.  To raise the Total Alkalinity, sodium bicarbonate, or sodium hydrogen carbonate is used.  In spa water chemistry, when the pH is low, the total Alkalinity usually low as well, so many spa chemical kits come only with sodium bicarbonate to raise both pH and alkalinity.

Other Spa Chemical Additives

Sanitation and corrosiveness take care of the most important aspects of spa water chemistry, so what is all this other stuff?  I have a bottle of green stuff, a bottle of blue stuff......

Metal Inhibitors - Since calcium, iron, and other metals are not easily removed, most spa chemical startup kits contain supplements to help keep them from staining or building up on the spa surfaces.  Most spa chemical kits come with a bottle of metal inhibitor like Metal Gone.  The entire bottle is used when first filling the spa, and each time after the spa is drained and refilled.  Spa Defender is a maintenance dosage,  used weekly, to prevent scale buildup on the spa surface, as well as in the heater, plumbing, and other equipment.  These sequestering or chelating agents can not be used with silver or copper based systems. because the render them ineffective.

Clarifiers  - Spa clarifiers, usually in the form of a blue liquid,  are coagulants, used to make particles larger and stickier, so that they can more easily be trapped by the filter.  I am not a big fan of clarifiers, because usually, if the water is cloudy or dingy, there is a reason for it - either the water is not in balance, not properly sanitized, or there the filter cycles are not long enough.  While chemical manufacturers recommend weekly doses, I prefer to solve the underlying cause.  If a clarifier is used, it should not be used on the same day as Defender or other sequestering agents.  The result is often a sticky greenish mess!  Most modern spas have very good filtration systems, and it is best, at least in my opinion, to let them do their job without "gumming them up".

Fragrances -

Aromatherapy has been used for centuries for relaxation, mood enhancement, and stress relief.  It's validity is unquestionable, and certain gentle fragrances trigger key emotions.  On the advice of a savvy realtor, when we were selling a house, we baked an apple pie during the showing.  Why? The aroma of fresh baked apple pie in the house gave a hint of nostalgia, and made the house seem like home!  We sold the house the very day after putting it on the market!

In spas and hot tubs, different fragrances enhance relaxation, vitality, and the sense of well being.  They also help to mask the smell of sanitizers.  Most spa fragrances are in the form of liquids or crystals that are poured directly into the water.  A little goes a long way - you aren't really trying to inundate yourself, rather, it is the subliminal fragrance that is most effective with aromatherapy.  If the fragrance is so strong that it overpowers, the user gets tired of it pretty quickly.  Also, fragrances contain oils or soaps that can effect the chemistry of the spa.  Just a hint of fragrance is all you need.

Some spas have built in fragrance dispensers. which use packages of pellets.  These pellets are usually placed in a chamber built into the air blower line, and are released into the water when the air blower is turned on.  The advantage to this type of system is that there is no residue, and the user can turn the fragrance off if it gets too strong.  On the down side, they are more expensive than liquid or crystal fragrances.

If a spa has a built in fragrance dispenser, it is still okay to use liquids or crystals.  Apply them directly to the water, as you would with a spa that is not so equipped.

Testing Spa and Hot Tub Water Chemistry

Knowing the basics of spa water chemistry is important, but how do you know what to put in?  Having a good way to test the water chemistry iv vital.  Test kits are available in two major forms.  Test strips are the easiest and fastest to use, and tells you everything you need to know in about 15 seconds.  Some people still prefer to use drops, and there is nothing wrong with that.  The important thing is that the water gets tested regularly.  When you first get your spa, the water should be tested at least daily, until you get to know the spa's "personality".  Once you can predict what the readings will be 10 out 0f 10 times, you can relax the schedule a bit.  Tests should also be done after heavy use, to make sure the sanitizer is not depleted, and that the water is still in balance. 

To use a liquid kit, a vile is filled with spa water to the specified indicator line, and a specific number of drops of reagent are added.  The color is then compared to a chart, which is usually attached to the vile.  from this, the user is able to determine the level of sanitizer, pH, Total Alkalinity, and other reading, depending on which test is being performed.  While most test kits have booklets or other instructions, with tables to tell you how much of what chemical to use, it is best to base the amount of chemicals to add on the directions provided by the label. on the chemical bottle.  While the strength of the chemicals is fairly standardized, it is best to let the test kit tell you what is needed, and let the chemical manufacturers instructions tell you how much. 

For Test strips, the strip is simply dipped in the spa water for about 1 second, wait 15 seconds, and compare each reading to the corresponding scale on the side of the bottle. 

If your test kit came with a booklet, READ IT! It is full of helpful information!







Pool Repair Spa Repair Pool Service Spa Service Pool heaters, Pool liners, in ground (inground) liners,  above ground liners, safety covers, spa parts, spa motors, spa controls spa diagnostics, pool equipment, pool pumps, spa pumps, pool motors, heaters,  Oklahoma City Area, including Bethany, Edmond, El Reno, Mustang,  Zip Codes include Moore, Yukon, Warr Acres, and Metro OKC.    zip codes include:  73003, 73008, 73013,73034, 73083, 73036, 73059, 73064, 73090,73099, 73064, 73101, 73102, 73103, 73104, 73105, 73106, 73107, 73108, 73109, 73110, 73111. 73112, 73113, 73114, 73115, 73116, 73117, 73118, 73119, 73120, 73121, 73122, 73123, 73124, 73125, 73126, 73127, 73128, 73129, 73130, 73131, 73132, 73134, 73135, 73136, 73137, 73139, 73140, 73141, 73142, 73143, 73144, 73145, 73146, 73147, 73148, 73149, 73150, 73151, 73152, 73153, 73154, 73155, 73156, 73157, 73159, 73160, 73162, 73163, 73164, 73165, 73167, 73169, 73170, 73172, 73173, 73178, 73179, 73184, 73185, 73189, 73190, 73194, 73195, 73196, 73197, 73198,


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Acid Rain

I've often heard people say "my acid is low".  Actually, what they mean is the pH is low.  The more acidic the water is, the lower the pH.  If the pH is low, the worst thing you could do is add acid!

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