Upkeep & Maintenance

For safe and proper usage of your hot tub, maintenance is key. Hot tubs need to be hygienic, which is done using chemicals. To determine what chemicals, need to be added to balance the water, you will need to do various tests. For personal use of hot tubs, this should be done at least once a week. The easiest way to do this is to perform a titration test. These are chemically treated strips that are used to determine acid and base demands, alkaline levels, and calcium hardness. You will need balanced water with the right levels to prevent scale and corrosion.

Your spa will come with these instructions and the installation team will be able to walk you through how to check your hot tub levels. In addition to this, you will need to add sanitiser to keep bacteria at bay, the most popular forms are bromine or chlorine.

In addition to regularly checking your water levels, it is recommended that the hot tub is drained, cleaned, and refilled at least once a year. This includes cleaning the vinyl lining and replacing the filter cartridges. The easiest way to do this is to hire a hot tub engineer to service your machine, this way they will be able to prevent any issues from occurring, and it takes the pressure off your shoulders.

If you are unsure on any of the terminology relating to your hot tub, you can refer to our glossary.


Put the cover on the tub when not in use. If your tub is filled with water but you aren't going to use it for a prolonged period - remove the cover once a week for 30 minutes to provide ventilation for the tub.

As well as reducing operating costs, stopping leaves from falling into the tub, and stopping children from climbing into the tub unsupervised, the cover also protects against UV radiation. UV radiation may be harmful to the tub body without water in it. Damage caused to the tub body by the sun is not covered by the guarantee.


Checking the water levels & sanitization.

Water hardness – recommended value: 8 – 12 nK

This value is determined by the amount of dissolved calcium and magnesium salts and minerals. Hard water contains too much of these dissolved materials, which will result in scaling. It can cause significant damage to the tub wall, the piping and the filter, as well as the heating and mechanical units. Water hardness cannot be reduced by chemical treatment, and only scaling can be prevented. Soft water can be produced by the water softener with resin tank used for this purpose. Hot tubs should be used with 8-12 nK° soft water. (nK°=German hardness).

Setting the pH value – recommended value: 7.2 – 7

The first important indicator is the water’s pH value. The pH value is measured on a scale of 0 to 14, where a value of 7 is considered neutral. Below that, water is acidic; above it, alkaline. The pH value of human eye is around 7.5. Over 7.8, water irritates bathers’ eyes. Experience shows that most of the problems are caused by a pH value that is too high. Inappropriate values reduce the effect of the disinfectant. The pH value of water is normally increased while the tub is not in use, and therefore, mostly pH reducers must be used.

Recommended chemical: pH reduce

pH reducer granules (100%) – package: 1000g It can be used together with any disinfectant; these pH reducer granules are highly effective.
Dosage: in order to reduce the water pH value by 0.1, add 1kg of pH reducer granules to 100 m3tub water. It is recommended to add at the water inlet or at several points on the tub. Dissolve it in tap water before use (1kg pH reducer granules in 10 l water)

Wellis Crystal bio disinfectant

This disinfectant kills or neutralizes microorganisms (bacteria, algae, fungi, viruses) present in water. Microorganisms are small microscopic forms of life that are not visible to the naked eye, and are constantly transferred into the water by rain, wind, or bathers. If they are not destroyed, they will be transferred by water from one person to another (causing illness or infection). Organic matter present in the hot tub water may turn the water opaque, or cloudy.

Recommended chemicals: Wellis Crystal 100% bio disinfectant

Pack size: 2×1 litre
Chlorine-free disinfectant with a concentration optimized for hot tubs and small hot tubs. It can be used for all tubs equipped with a water circulation and filtering system. 100ml of Wellis Crystal is required for 1 m3 tub water. The presence of disinfectant in the water can be detected with the use of various testers. Aquacheck 5 in 1 tester.


Bubbles and colloidal contamination accumulate in different sizes of foam clots on the water surface. This foam is mostly formed by particles removed by water from human skin, cosmetics, body lotions, etc. and by the mixing of various chemicals. It jeopardizes the maintenance of aesthetic quality and cleanliness of your hot tub water.
Foaming is a condition in which there are foam clots or a continual foam layer present on the water surface 30 seconds after the massage motors are stopped.

Recommended chemical: Foam Stop 1000g – Anti-foam liquid for tubs

Pack size: 1000g Effectively decreases foam formation caused by body lotions or other materials. Dosage: depending on foaming intensity, until foam disappears. After adding, wait until the material is thoroughly dissolved in the tub.

Filter cartridge cleaning

Filter cartridges are designed to remove impurities from the tub water. Therefore, keeping them clean is essential. In the case of highly contaminated filter cartridges, the system may not provide the proper amount of water flow. In this case, the control unit may disable operation if there is an error message displayed on the operating unit. The filter cartridge(s) must be cleaned weekly. It is recommended to soak the filter cartridges in the chemical solution Filter Cleaner for 24 hours.

De-energize the tub before removing the filter cartridge(s). In the case of operating without filter cartridge(s), there is a danger of damaging the circulation pump. Unscrew the filter cartridge(s) and use a strong jet of water to remove any deposited impurities from between the lamellas. Never use the tub without a filter cartridge. It is recommended to have an extra filter cartridge on hand

The filter cartridges must be replaced every 3 months.

The tubs currently have three different filter housing designs:

  1. Skimmer housing
  2. Floating filter housing
  3. Wall-mounted filter housing

Filter replacement in a skimmer:

  • Remove the filter cartridge by turning it anti-clockwise
  • While still in the water, tilt the filter cartridge a bit sideways to allow air to leave the cartridge
  • Screw in the cleaned or new filter cartridge by turning it clockwise


  • Exchange the water (except for tubs equipped with In-Clear)
  • Find the drain in the tray and remove the closing cup.
  • Screw in its place the metric spacer provided with the tub.
  • Turn off the larger receiving part anti-clockwise as far as you can.
  • Then pull the receiving part towards yourself – the water will start to flow out of the tub.
  • After all the water is drained from the tub, repeat the above-described steps in reverse order.

Filling up the tub with water: please note that the tub must always be filled through the filter housing. If it is not, air can get into the circulation system. In this case, the tub heater may be damaged - replace the filter cartridges with new ones. In case it is necessary, replace the UV bulb, or order a replacement.