ChloroKlean Chlorine Dioxide

Chlorine dioxide swimming pool water treatment explained

Chlorine dioxide is used in swimming pool water treatment as an oxidising treatment. Pool owners usually look at it when they want help with water quality issues such as unpleasant odours, organic contamination and general water cleanliness. It is different from routine pool sanitiser products, so it is important to check how it fits into your normal treatment plan before use.

For UK pool owners, the key point is that chlorine dioxide treatment should be used exactly to the product label and should be matched to the size of the pool and the condition of the water. It is sensible to test the water first, then apply treatment carefully, circulate the pool water well and re test before swimming.

Is chlorine dioxide the right swimming pool water treatment for your pool?

If you are comparing chlorine dioxide swimming pool water treatment with standard pool chlorine or bromine products, the main difference is purpose. Routine sanitisers are part of everyday pool care, while chlorine dioxide is generally considered for specific water treatment needs. If your goal is regular day to day sanitising, keep your normal pool care products and testing routine in place unless the product instructions say otherwise.

ChloroKlean chlorine dioxide for hot tubs and swimming pools. A powerful ClO2 oxidiser that penetrates and strips biofilm where chlorine and bromine cannot reach, clears the bacteria and organic waste behind cloudy water, and leaves it fresh with no chloramine smell.

Sizes and prices

When you need it

How to use

  1. Test sanitiser, pH and alkalinity in the hot tub or pool.
  2. Confirm pH 7.2-7.6 and alkalinity 80-120 ppm.
  3. Measure the correct dose for your water volume (see the dosing table).
  4. With the pump running, pour the measured dose slowly into the skimmer or across a return; it activates in situ in the water.
  5. Circulate uncovered for 30 minutes (hot tub jets on full; pool pump on full).
  6. Wait at least 1 hour before bathing or swimming, then retest sanitiser.

Dosing guide

Single deep-clean treatment for hot tubs and swimming pools. Scale the dose to your water volume and always retest before redosing. For large or commercial pools, follow the product label or contact ChloroKlean technical support for a dosing plan.

How it works

ChloroKlean stabilised chlorine dioxide (ClO2), a liquid preparation that activates in situ when added to water, releasing ClO2 in dilute aqueous form for safe hot tub and swimming pool dosing. Chlorine dioxide is widely used for pool, spa and public-area water treatment.

Chlorine dioxide is a selective oxidiser that targets sulphur and nitrogen bonds in organic waste and biofilm. Unlike free chlorine it does not react strongly with ammonia, so no chloramines form, and it stays effective across a wide pH range. It penetrates the biofilm matrix and disrupts the bacteria living inside it.

Free chlorine and bromine react at the surface of biofilm and rarely penetrate it. ClO2 cuts through to the colonies inside, lowering routine sanitiser demand in hot tubs and pools without forcing a full water change, and with no harsh chlorine smell.

Frequently asked questions

Can I use chlorine dioxide in hot tubs?

Yes. ChloroKlean chlorine dioxide is ideal for hot tubs and spas. It strips biofilm from the pipework, oxidises bather waste and brings sanitiser demand back down, all without adding chlorine or leaving a chloramine smell.

Can I use chlorine dioxide in swimming pools?

Yes. Chlorine dioxide is a proven swimming pool treatment. It penetrates biofilm, oxidises the organic waste that drives up sanitiser demand, and produces no chloramines, so the water stays clear with no harsh chlorine smell.

How often should I dose it?

Use it every 4 to 6 weeks as a deep oxidative clean in a hot tub, or whenever sanitiser demand creeps up. In swimming pools, dose at the start of the season and after heavy bather load.

Does it replace my regular sanitiser?

No. Chlorine dioxide is a periodic biofilm and shock treatment; day-to-day sanitising of your hot tub or pool still needs chlorine or bromine.

What is ChloroKlean?

ChloroKlean is our chlorine dioxide brand for pool and spa water, made by Spa Trade Group, the same group behind ClearSpa. The ChloroKlean range covers hot tubs, swimming pools and public-area water.

Is it safe for inflatable and acrylic hot tubs?

Yes. At recommended doses chlorine dioxide is safe for vinyl, acrylic and fibreglass hot tubs, swim spas and pool surfaces.

Will it work in salt-water hot tubs and pools?

Yes. Chlorine dioxide is compatible with salt chlorination and does not damage the cell.

Is there a complete kit?

The ChloroKlean Spa System Core Kit and Pro Care Kit pair chlorine dioxide with a clarifier, test strips and cleaners for whole hot tub care. Contact us for kit availability.

How is chlorine dioxide different from chlorine?

Chlorine dioxide is a selective oxidiser that forms no chloramines and works across a wide pH range. It penetrates biofilm in hot tub and pool pipework where free chlorine cannot reach.

Why does it stop the chlorine smell?

That smell is chloramines, formed when chlorine reacts with bather waste. Chlorine dioxide oxidises the waste without forming chloramines, so the smell and eye sting clear.

What does PT2 mean for pool and spa treatment?

PT2 is the biocide product-type category for disinfectants used in pools, spas and public areas. It is the application chlorine dioxide is best known for in hot tub and swimming pool water.

Will it interfere with my water tests?

Wait 30 minutes after dosing before testing free chlorine or bromine so the chlorine dioxide can vent.

Cloudy water in the hot tub or pool?

Released biofilm fragments. Run the filter and dose a clarifier; the ChloroKlean Spa System includes one.

Chlorine dioxide vs non-chlorine shock?

Both are non-residual oxidisers. Chlorine dioxide penetrates biofilm; non-chlorine shock (MPS) clears bulk-water organics. Use chlorine dioxide monthly and MPS weekly.

Chlorine dioxide vs bromine for hot tubs and pools?

Bromine is a daily sanitiser. Chlorine dioxide is a periodic biofilm and deep-clean treatment that forms no chloramines; use it alongside your bromine or chlorine routine.