Chlorine Shock Treatment Alternatives

Potassium Monopersulfate

The use of Potassium Monopersulfate, a non-chlorine shock treatment, has significantly increased in both use and popularity among hot tub and spa owners over the last 10 years.

The benefits of using a non-chlorine shock like Monopersulfate instead of a chlorine or bromine shock include reduced odor, less irritation to your eyes and skin and it requires only a short waiting period before soakers and bathers can re-enter the water.

MPS was developed by DuPont and acts as a highly effective oxidizing agent when used in hot tubs and spas. When used at full strength, many hot tub and spa owners refer to MPS as the Non-Chlorine or Non-Bromine “Shock Treatment Alternative” because of its effectiveness to destroy and remove contaminants and bacteria.

Chlorine Shock

Chlorine is the most widely used water shocking sanitizer for hot tub, spa and pool owners because of its ability to quickly and effectively sanitize pathogenic disease-causing bacteria and viruses.

Surprisingly, only 10 per cent of the chlorine added to spa water goes on to kill living organisms. The other 90 per cent of the chlorine oxidizes (destroys) waste products in the water, such as sweat, skin particles, and sun screen introduced into the water by bathers. Chlorine also has to oxidize dust, bugs or grass, which always seem to find their way into the water all by themselves.

The byproducts of chlorine oxidation are chloramines, also known as combined chlorine. Chloramines have a very strong chlorine odor, and they cause nasal and eye irritation. Shocking the water with chlorine will eliminate excessive chloramines, but it requires raising the spa chlorine level to approximately 10 ppm.

After super-chlorinating the water, bathers must wait until the chlorine residual comes down to the acceptable range, between 1 ppm and 5 ppm, before getting back in the water. This can take hours, depending on how high the chlorine level gets. It is difficult to add just the right amount and the higher the level gets, the longer bathers will have to wait to get in.

Non-Chlorine Shock

The negative side-effects of using chlorine as a sanitizer have many hot tub, spa and pool owners turning to non-chlorine or hybrid chlorine/bromine sanitizing and shocking alternatives. Monopersulfate is a non-chlorine shock treatment that has become very popular with hot tub and spa owners and requires only a short waiting period before soakers and bathers can re-enter the water.

It also cuts down on the odors and irritation caused by elevated levels of chlorine. With the rising popularity of mineral purification systems, the increase of hot tub and spa owners switching from chlorine to non-chlorine shock treatments is growing faster than ever before and shows no signs of slowing down anytime in the near future.

Using Monopersulfate With Chlorine

Monopersulfate can eliminate wastes in hot tubs and spas without the unpleasant side effects of chlorine. While it cannot effectively sanitize or kill all bacteria in a hot tub or spa, monopersulfate can effectively be used to shock the water.

This allows soakers and bathers to return to the water much sooner than with chlorine shock, typically less than 30 minutes after the monopersulfate shock has been added to the water. Monopersulfate eliminates impurities through oxidation, while conserving the chlorine residual for killing bacteria.

Another added benefit is that monopersulfate doesn’t leave behind any irritating or unpleasant byproducts when it oxidizes wastes.

Using Monopersulfate With Bromine

Another popular choice for sanitation in hot tubs and spas is bromine. Bromine is a good alternative to chlorine because it’s more stable in hot water, doesn’t produce the same strong chlorine odor and is still an effective sanitizer.

Bromine is slightly more expensive than chlorine, but the benefits are worth it to many hot tub and spa owners.  In a bromine system, Monopersulfate is an activator for the bromine that has been used up and converted into a non-active form.

Monopersulfate oxidizes waste as in the chlorine system, but it also has the capability of reactivating the bromine. This allows it to begin sanitizing and oxidizing your water all over again, whereas chlorine is not capable of this type of reactivation.

As with chlorine, using monopersulfate with a bromine system has the added benefit of allowing soakers and bathers to return to the water faster than with Chlorine or Bromine only shock, typically less than 30 minutes after the monopersulfate has been added to the water.

Using Monopersulfate with Mineral Purification Systems – Another popular and growing form of non-chlorine alternative sanitation is Mineral Purification Systems. These systems use dissolved minerals such as copper to kill algae and silver to kill bacteria.

Minerals can keep your hot tub or spa water safe from pathogenic organisms, but minerals are incapable of destroying waste products and debris. Using monopersulfate with your mineral purification system solves the oxidation problem and leaves a residual amount in your system to oxidize future wastes and debris.

Monopersulfate dissipates very quickly in the presence of high levels of chlorine or bromine, but the residual levels stay in place much longer in mineral purification systems where the levels of chlorine and bromine are much lower.

Testing Monopersulfate Levels – In order to maintain clear, clean water, the Monopersulfate level should be measured after each use, especially if it is being used as the primary shocking agent. This ensures proper oxidation of wastes and safe clear water for soakers and bathers.

Testing Tip – Since chlorine is a strong oxidizer, the readings on most monopersulfate testing kits are tainted due chlorine interference and can cause false positive test results. The trick to getting an accurate reading in the presence of chlorine is to use a subtractive testing method.

Buy a test kit that allows you to measure both the water chemistry’s total oxidized value and the chlorine level. The total oxidized value measurement includes both chlorine and monopersulfate.

The chlorine level test measurement detects the chlorine, but not the level of monopersulfate. Subtract the chlorine level from your total oxidized value measurement and you will get an accurate reading for your hot tub or spas monopersulfate level.