Hot Tub Decontamination

The other signs of spa problems include cloudy water, slime formation and foul or musty odors eliminating from the spa. You may also develop skin rashes because of this, which in turn may develop after some days of using the spa in this condition.

Too much contamination in the spa water can lead to the presence of excessive amounts of bacteria in the biofilm that develops in the plumbing system and spa filter. This, in turn, will be resistant to normal sanitizing methods of your spa.

If you find any of this developing on your spa, have bought a used spa or intend to service a spa because of negligence on your part, you may have to follow decontamination procedures on the spa - whether an in ground or portable spa.

This decontamination procedure has to be adapted as a precaution because standard cleaning, draining and replacement of the spa water will not correct the problem. In fact, it is advisable to consider decontamination if and when you convert to a new or alternative spa sanitizer system.

There is an easy disinfection procedure that you can use to bring a spa into good health. This procedure consists of three steps; decontamination, water replacement and verification.

Phase 1 - Decontamination

Spa covers

To decontaminate spa covers, it has to be thoroughly cleaned, while placing emphasis on the underside. It's preferable to use Clean All Spray and to seal the cover with 303 Protectant which will help discourage mildew formation on the spa cover.

Replace the hot tub cover if it is in bad condition, or water logged. This is because covers only end up getting infested with mold, bacteria and mildew which in turn continuously inoculates the spa water with additional microorganisms.

Spa Filters

It is important that you remove and inspect your filter cartridges and if they are older than one year, or in bad condition, they have to be discarded. If the cartridges are serviceable, then clean them using Power Soak Filter Cleaner by following the instructions on the label.

Once the cartridge is cleaned and rinsed, it has to be completely submerged in a solution of Dichlor Chlorine for a few hours. (Mix a teaspoon of Dichlor for 3-5 gallons of water). Also make it a point to also inspect and clean the interior of the filter housing and skimmer.

Hot Tub Vessel Super chlorination

Next comes the decontamination of the spa. The water has to be first super chlorinated with a minimum of 1000 ppm with Dichlor Granular Chlorine. This has to be first pre-dissolved in a plastic bucket of water to prevent damage to the spa's acrylic surface because of direct contact with chlorine granules.
When mixing Dichlor Granular Chlorine, you have to mix 4 teaspoons for 100 gallons of water, ¾ cup if you have 250 gallons of water, 1 ½ cups if you use 500 gallons of water and 3 cups of if you use 1000 gallons of water.

This done, you have to raise the water level of the spa to about ½ or an inch above the normal high water mark of the spa. Then you have to circulate spa water in high speed for half an hour, while closing the spa cover.

This has to be done with jets on maximum after which the air injector has to be switched on and off at five minute intervals. This is to help in the disinfection of air lines. If you have an electric air blower in your spa, you have to run it for a minute, every five minutes.

It is advised not to inhale any vapors or mists that are eliminated from the spa during the decontamination process.

Flushing Spa System

Before draining the spa, you have to add some Spa System Flush by following the label directions. Then let water circulate for half an hour, while turning air injectors and the blower on and off at intervals.

Adding Spa System Flush to your spa helps to break up and dissolve inaccessible biofilm from the plumbing system of the spa. This helps in completing the spa decontamination process.

Phase 2 - Water Replacement

Once the decontamination of the spa is completed, you have to reinstall the cleaned and sanitized filter or if required, add a new filter cartridge. Then the spa has to be refilled with fresh water and then balance the water while placing emphasis on total alkalinity and pH levels of the water.
However don't add any sanitizer to the spa at this moment; instead move on to the next phase, the verification of the spa.

Phase 3 - Verification

This is the final and most important step of decontamination of the spa. As the contaminants deplete the water of free chlorine residual, the refilled spa has to be shocked with 10 ppm of Dichlor Granular Chlorine after pre-dissolving it in a plastic bucket of water. Add about 2 tablespoons for 400-500 gallons of water and then check the spa water using Universal Test Strips to ensure that it is about 10ppm.

This done, let the spa circulate for 8 - 12 hours, with the spa cover on, to avoid the degradation of chlorine level because of sunshine. If your spa is uncovered, this will have to be done overnight.
After circulation of the water, the free chlorine level has to be tested using Universal Test Strips. The decontamination process is successful if you get residual free chlorine reading on the test strips.
However if no free chlorine residual is present, there may be excessive demand which indicates the presence of decontamination, which in turn depletes the chlorine. So if there is no free chlorine, all you have to do is to repeat the decontamination procedure.

On verification of the successful decontamination, you have to add the sanitizer system of your choice to the spa. Remember that any residual chlorine present in the spa depletes in a few days time, to make the spa compatible with most sanitizer systems.
Make it a point to maintain your sanitizer and to use Spa System Flush with every water change to prevent the need of future total decontamination. However if the residual chlorine is above 5 ppm after verification, this can be reduced to 3-5 ppm by draining some spa water and then replacing it with fresh water. You could also let chlorine to dissipate naturally before using the spa.

Read more about anything and everything to do with hot tub care and spas in our Spacyclopedia.