High demands are placed on the cleaning and maintenance of bathing water, whichi in turns means high demands on water chemicals intended for spa baths. The high water temperature means that microorganisms and bacteria thrive. As the water is filtered and reused several times, extra disinfection is needed. The pipe systems of spas and hot tubs can hide nasty surprises and therefore require extra attention.

4 simple tips for maintaining water hygiene if you have a treatment plant

  1. Always shower before going in the water
  2. Use bactericides before and after bathing
  3. Check and adjust pH levels at regular intervals
  4. Clean the filter cartridge frequently and run the filter system often enough.

It is not difficult to keep the water clean in your spa or hot tub (if it has a filtration system) when you use the right products at the right time. We have listed here the 4 most important steps that ensure a high water quality.

Chlorine and chlorine-free disinfectants and how they are used

As a general rule, chlorine is the best disinfectant to kill and protect against bacteria. Active oxygen is a chlorine-free alternative that effectively removes bacteria when it is added, but it does not have the long-lasting effect that chlorine has. We have tested this extensively and found that the best method by far is to use fast-dissolving chlorine (Spa Tab 5) and active oxygen in combination. Chlorine tabs and the 3-step CombiTabs work the best. For example; Use three tabs CombiTabs per week and two SpaTab 5 tabs. One tablet of SpaTab 5 should also placed in the water a few minutes before entering the water and one tablet after you are done. Easy to remember and efficient! TIP! If you are allergic to chlorine, use just CombiTabs! In other cases use SpaTab 5 or combination as described.

Chlorine is the most widely used disinfectant

Chlorine purifies the water of both organic and inorganic impurities. Chlorine is therefore used in most swimming pools, as it keeps the water visibly clean and hygienic at the same time. When using fast-dissolving SpaTab 5, one tablet is added 10 minutes before a bath and another tablet after, this is a suitable dosage for a spa with 1000-1200 liters of water volume.

If you desire a chlorine-free alternative, active oxygen can be used as a disinfectant.

OxyChock - Granulated active oxygen

The product OxyChock is a granulate that gives off oxygen (active oxygen) when dissolved in water. It is the high content of oxygen that kills the bacteria. Unlike chlorine, it quickly disappears from the water. Already four hours later, it can hardly be measured in the water and then has no protective effect. Therefore, it is added more often versus chlorine.

Ideal value for active oxygen in the water is 3-5mg/l (ppm)

A popular chlorine-free product is CombiTabs where the active disinfectant is active oxygen. It is a "3-step" tablet which, in addition to active oxygen, contains anti-algal agents as well as agents that prevent deposits. Of the CombiTabs tablet, 3 tabs per week is suitable for maintaining 1000-1200 liters of water. It can also be combined with two SpaTab 5 (fast-dissolving chlorine) per week.

Even if you have chosen a chlorine-free disinfectant only, you can still carry out a shock treatment with chlorine every 14 days.

The chlorine-free disinfection method is effective in the short term. But within a few weeks, microorganisms and bacteria that the chlorine-free products cannot deal with, can thrive in the water. Especially during hot periods. You should therefore disinfect the water thoroughly every 14 days with a chlorine shock treatment that is guaranteed to remove all bacteria from the pool water. Active Oxygen and Chlorine as we've mentioned, are compatible - you can therefore mix chlorine with active oxygen products. If you do not tolerate the smell of chlorine, wait to take a bath until the chlorine odor has disappeared.

When you drain the water, we recommend that you pour it into the communal sewer system so that it reaches the treatment plant.

Chlorine products in concentrated form must not be poured into the sewage system but must be left in the packaging as "hazardous waste" at the recycling station.


No matter which disinfection form you choose, it is always important to take a shower every time before using the bath to get rid of dirt and makeup.

We have listed here the 4 most important steps to ensure high water quality

STEP 1 - Measure and adjust the pH levels

You measure the pH value with Test Strips, which quickly and easily show the pH level.

A pH value above 7.4 is lowered by adding pH Minus granules. 10 grams is sufficient to lower the pH value 0.2 units in 1000 liters of water.

A pH value below 7.0 is increased by adding pH Plus granules. 10 grams is enough to raise the pH value 0.2 units in 1000 liters of water.

10 grams = a teaspoon

After filling the bath with water, first measure the acidity of the water. That is, if the water is in balance and has a neutral pH value. Check PH value at least once a week.

High pH (alkaline water) causes:
  • reduces chlorine effectivness
  • skin irritation
  • limescale deposition
  • cloudiness
Low pH (acidic water) causes:
  • corrosion and damage ofx mechanical components
  • irritated eyes and mucous membranes
  • Damage to spa surfaces

The value to aim for is 7.2 - 7.6 . The pH is lowered with pH-minus (sodium bisulfate) and raised with pH-plus (sodium carbonate).


STEP 2 - Disinfect the water with a shock treatment

To prevent the bacteria from forming in the water, water preservatives are used as disinfectants. Water care products are so-called oxidants, which include products based on chlorine or active oxygen. The disinfectants must be added to the water continuously, but at start-up the water is given a shock treatment, which means that the water is given a higher dose of disinfectant than normal. This is to effectively disinfect the water completely and remove coatings and discolorations.

Shock Treatment Chlorine Method
As a "shock treatment", SpaTab 5, which is a fast-dissolving chlorine in tablet form, can be used. SpaTab 5 also contains a chlorine stabilizer that protects the chlorine from degradation from sunlight.

Bound chlorine and free chlorine

Chlorine that remains in the water after the disinfection effect has subsided is called "bound chlorine". If there is a lot of chlorine smell, although the test strips show that there is no chlorine, the chlorine may have become bound to chlorine and then shock chlorination is required. Bound chlorine can also be reduced by diluting with fresh water. When talking about the value "Free chlorine", it is the amount of effective disinfectant chlorine in the water that is meant. The ideal value is 0.5 -1.5 mg / liter (ppm).

After a chlorine shock treatment, wait until the value of free chlorine has dropped to between 1-1.5 mg / liter (1-1.5 ppm). This can be measured with test strips. If a shock treatment with chlorine is done in the evening, the water is ready to bathe in the next morning.

Shock Treatment Chlorine Free Method
OxyChock granules based on active oxygen are used as chlorine-free shock treatment. If you use the chlorine-free method with active oxygen, we recommend shock-treating the water with OxyChock once a week, as active oxygen and its disinfectant properties disappear from the water faster than chlorine does.

STEG 3 - Clear water

If the water feels cloudy. Then it may be necessary to add an agent which binds the small liquid particles together in larger units, which can be more easily captured by the filter or with a pool vacuum and gives a crystal clear bath water completely naturally.

SeaKlear was originally developed to clear cloudy water in connection with underwater photography in nature. SeaKlear is a natural product that does not cause any damage to the environment.

SeaKlear makes the water crystal clear in just a few minutes. When used in swimming pools, it simultaneously reduces the formation of chloramines (also known as "combined chlorine"), which can cause irritation to the eyes and nose. You can actually reduce your chlorine consumption by as much as 40% by using natural SeaKlear.

At the same time, SeaKlear removes oils, lotions and impurities, thus preventing cosmetics and soap residues from forming foam. SeaKlear is also beneficial for the water filtration system as it prevents the filter from becoming clogged with oil residues. This means that the filter is kept clean and that it works effectively much longer.

Swim & Fun SeaKlear can be used with both cartridge filters, Filterballs and sand filter systems.

STEP 4 – Filtration

It is not enough to just use chemical water care products to keep the water fresh and inviting. It is also necessary to filter the water efficiently through a filtration system, as well as regularly remove sediment and impurities from the water. Larger precipitation such as ex. leaves, grass and the like, should be collected with a surface water collection bag / skimmer. And when the bath is not in use, it should be covered with a lockable lid.


The fact that the water does not become clear (cloudy or misty water) is almost always due to poor filtration. Either to short filtration periods but more often because the filter cartridges are not clean and cannot take care of impurities.

Filter cartridges:

The function of a filter cartridge is to remove soil, sand, minerals, phosphates, deposits from bathers and other solids from the bath water.

Cleaning the filter cartridge: In addition to washing the filter with e.g. a massage shower, you also need to "deep clean" the filter cartridge. Although the filter cartridge may look clean, it still needs to be cleaned regularly. Minerals and other contaminants that are very difficult to detect can get stuck deep inside the filter fibers and thus cause problems with water flow. It is good practice to have an extra filter cartridge on hand. One filter should always undergo the deep cleaning and drying process while the other is installed. Deep cleaning doubles the overall life and power of the filter cartridges.

Note! If there is a problem with the heating, an unclean filter is a probable cause. Tip! In this case, remove the filter cartridge and try without it, and if it works, the filter must be cleaned or replaced with a new one. It is good to have an extra filter cartridge on hand.

Filter cleaning:

  1. Put the dirty filter in a bucket of water and add machine dishwashing detergent.
  2. Leave it in the mixture for at least 12 hours.
  3. Remove the filter and rinse it clean with e.g. a water hose or massage shower both from the outside and inside. Let it dry thoroughly. The filter should dry for at least two days before installing. Note! This last step is important regardless of what can is recommended elsewhere.