No smell, no stabiliser, and a residual that does not last

The best active oxygen for 2026

Active oxygen — potassium monopersulfate, or a peroxide preparation — is the chlorine-free route, and it is chosen for one reason that matters to a lot of buyers: no chlorine smell, no bleaching of swimwear, and no cyanuric acid accumulating in the water. What it gives up is equally concrete, and an honest page has to say so: active oxygen leaves very little residual disinfection. Chlorine sits in the water for days; an oxygen treatment is largely consumed within one, which is why every serious product on this shelf is sold alongside an activator — usually a low-dose algicide — that does the standing protection the oxidiser does not. A listing that sells the oxidiser without mentioning the activator is selling half a system. The figures to compare are the active content, the dose per cubic metre for a weekly treatment, and the pool size and temperature the maker considers suitable: above about 25–28 °C, most makers of these products stop recommending them for a main pool and confine them to spas and small volumes, because consumption rises with temperature. Then the format, granule or tablet, and whether it dissolves fast enough to be used the same day. We compare active content, dose per cubic metre, required activator, residual life and stated temperature and volume limits.

These parts, one figure beside another

1. 

   STEINBACH Sauerstoffgranulat 1 kg

   A one-kilogram chlorine-free oxygen granulate for first and continuous dosing, which its own listing states is combined with a matching liquid oxygen activator — sold separately.

   Active content

   Not published

   Dose per cubic metre

   Not published

   Required activator

   Yes — the granulate is stated to be combined with the matching liquid oxygen activator in the chlorine-free care system. The activator is not in this pack

   Residual life

   Not published. Stated to keep the water clear for longer with minimal effort

   Stated temperature limit

   Not published

   Stated volume limit

   Not published. Stated for all private pools — above-ground, in-ground and hot tubs. BAuA registration number N-110823

   Amazon reference

   B01N80FU15 (one reference across 4 Amazon marketplaces)

   EAN

   9008748008754

   • Suitable for first dosing as well as continuous dosing, stated
   • Works through a skimmer, a dosing float or a dosing lock — three routes published
   • Needs a separate liquid activator that is not in the pack

   Best for: A chlorine-free pool already running the matching activator

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2. 

   Bayrol Aktivsauerstoff Granulat 1,0 kg

   A one-kilogram active oxygen granulate whose title says outright that the Cristal active oxygen activator is additionally required. One bullet, and it names the system rather than the product.

   Active content

   Not published

   Dose per cubic metre

   Not published

   Required activator

   Yes — the title states the Cristal active oxygen activator is additionally required. It is the only listing in this family to put it in the title

   Residual life

   Not published

   Stated temperature limit

   Not published

   Stated volume limit

   Not published. Stated to be part of the system care for pool water with active oxygen

   Amazon reference

   B00YULF4HY (one reference across 2 Amazon marketplaces)

   EAN

   4002369321860

   • The only listing in this family to state the activator requirement in the product title
   • Names itself as part of a system rather than as a standalone treatment
   • One bullet, and five of the six figures on this shelf are absent

   Best for: Replenishing the granulate half of a Cristal active oxygen system already in use

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3. 

   Bayrol SpaTime SpaTime Aktivsauerstoff-Granulat 1 kg

   A one-kilogram active oxygen granulate for hot tubs with immediate action, stated free of heavy metals and dissolving quickly without residue.

   Active content

   Not published

   Dose per cubic metre

   Not published

   Required activator

   Not published — no activator is mentioned in this listing

   Residual life

   Not published. Immediate action stated

   Stated temperature limit

   Not published

   Stated volume limit

   Not published. Stated for hot tub water

   Amazon reference

   DE B00C66QE0G · GB B00CAGF3O0 · FR B00CAGF3O0 · IT B00CAGF3O0 · ES B00CAGF3O0

   EAN

   4008367321505

   • The only listing here to state that it is free of heavy metals
   • Immediate action stated, which suits a hot tub used the same evening
   • No dose, no active content, no chemistry

   Best for: A hot tub run chlorine-free, treated shortly before use

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4. 

   HERRLAN PSM Aktivsauerstoff 12 %, 5 L

   The only liquid on this shelf: a stabilised 12 % active oxygen in a five-litre canister, with a published twelve-month shelf life and explicit storage instructions for its degassing cap.

   Active content

   12 %, stabilised — the only concentration published in this family

   Dose per cubic metre

   Not published

   Required activator

   Not published — no activator is mentioned

   Residual life

   12-month shelf life from receipt, stated, with correct storage

   Stated temperature limit

   Not published as a water temperature. Stated to be stored cool so the degassing closure works correctly

   Stated volume limit

   Not published. Stated for pools, swimming basins, above-ground pools, hot tubs and spa and wellness installations, private and commercial. BAuA registration number N-77387

   Amazon reference

   B0H3P7NPTT (one reference across 1 Amazon marketplace)

   EAN

   4068454497957

   • The only product here to publish a concentration — 12 %
   • The only one to publish a shelf life, and it is short enough to matter: twelve months
   • Five litres of liquid is heavy and has a published twelve-month life

   Best for: A pool or spa run on liquid active oxygen, where a five-litre canister is used within a year

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5. 

   GiDeli Aktivsauerstoff 5 kg, sodium percarbonate

   The only product on this shelf to name its chemistry — sodium percarbonate — and the only one to publish a dose: 100 to 200 g per 10 000 l at season start, then 50 to 100 g weekly.

   Active content

   Not published as a percentage. The chemistry is named: sodium percarbonate — the only compound named in this family

   Dose per cubic metre

   100–200 g per 10 000 l at the start of the season, then 50–100 g per 10 000 l weekly, with the pH set to 7.0–7.4. The only dose published in this family

   Required activator

   None — stated to go into the water neat or through the skimmer, without mixing further products

   Residual life

   Not published. Opened containers stay usable if kept dry and closed, stated

   Stated temperature limit

   Not published

   Stated volume limit

   None stated as a maximum. Loose granulate can be weighed out for basins under 10 000 l. The product is stated to be oxidising and must be stored closed and out of reach of children

   Amazon reference

   B0H7RFNFSK (one reference across 3 Amazon marketplaces)

   EAN

   5906168839399

   • The only listing here to name its chemistry and the only one to publish a dose
   • Needs no activator, where three products on this shelf do
   • No active oxygen percentage, so the dose cannot be compared with the 12 % liquid here

   Best for: A pool dosed by weight to a published figure, without a second product to buy

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6. 

   POOL Total Aktivsauerstoff-Set with activator

   The complete system in one box: active oxygen with its activator and a clarifier, which is what three of the granulates on this shelf need and do not include.

   Active content

   Not published

   Dose per cubic metre

   Not published. Precise dosing is stated as part of the complete set

   Required activator

   Included — the set contains the activator and a clarifier. It is the only complete system in this family

   Residual life

   Not published. Long-lasting action stated, with active oxygen giving continuous disinfection

   Stated temperature limit

   Not published

   Stated volume limit

   Not published. Stated suitable for all pool types and hot tubs

   Amazon reference

   B09TWC4583 (one reference across 1 Amazon marketplace)

   EAN

   4251002859479

   • The only complete active oxygen system on this shelf — nothing else has to be ordered
   • Includes a clarifier as well as the activator, which the other products do not
   • No dose, no active content, no chemistry, no component weights

   Best for: A first move to chlorine-free care, where the whole system should arrive in one delivery

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7. 

   Cristal Aktivsauerstoff 5 in 1, 4.48 kg

   A five-function active oxygen care in pre-dosed twin-chamber sachets, stated for pools from about 15 m³, applied weekly with the filter running.

   Active content

   Not published

   Dose per cubic metre

   Not published as a weight. Pre-dosed twin-chamber sachets, applied ideally weekly, with the dose increased according to weather and number of bathers

   Required activator

   Not published as a separate purchase. Five components are supplied in the pre-dosed twin sachets

   Residual life

   Not published. Weekly application stated

   Stated temperature limit

   Not published. The dose is stated to be increased according to the weather

   Stated volume limit

   A minimum rather than a maximum: stated suitable for all pools from about 15 m³. BAuA registration number N-10347

   Amazon reference

   B0725P8WTG (one reference across 3 Amazon marketplaces)

   EAN

   4002369992138

   • The only product here to publish a minimum pool size, which is an honest limit rather than a claim
   • Pre-dosed twin-chamber sachets, so nothing is weighed and nothing is mixed wrongly
   • Not for pools under about 15 m³, by the maker’s own statement

   Best for: A pool of 15 m³ or more, dosed weekly without weighing anything

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