Stabilised Chlorine Granules

Regular sanitising is essential for any pool maintenance routine that is required to keep the water clean. This is done through the application of pool chemicals to remove bacteria and viruses, as well as minimising algae build-up.

Choosing to use stabilised chlorine granules for hot tubs, spas or swimming pools affords you a versatile sanitising solution. Granule dosage can be adjusted to the exact volume of water you have, giving you tighter control over the level of chlorine you’re adding.

Stabilised chlorine granules can be used for regular sanitising and shock treatments*, meaning you can perform two types of cleaning using a single product. This can be especially handy if you want to minimise the amount of chemicals you need to store.

*We only recommend using stabilised chlorine granules as a shock treatment on above ground pools, which are only used during the summer. Using stabilised chlorine granules as a shock treatment on a large in-ground pool will eventually lead to a high stabiliser level.

Stabilised chlorine granules – at a glance

Chemical Sodium Dichloroisocyanurate 56% strength.
Function A granular form of chlorine sanitiser for pools and spas. Also used as a shock treatment on small above ground pools.
Pool Dose 100 grams increases the chlorine level by 1ppm in a 10,000 gallon pool.
Pool Shock Dose Add 750 grams per 10,000 gallons of pool water. This might need to be doubled or even trebled depending on how much algae is present.
Spa Dose 5 grams (a teaspoon) increases the chlorine level by 2.5ppm in a 1,000 litre spa.
Dosing Method Dissolve granules in warm water in a plastic bucket and distribute around the pool.
Blog Visit our blog to read more about using Stabilised Chlorine Granules.

*Please note the doses shown above show how much chlorine is needed to raise the level in pure clean water. Any contamination in the water will use the chlorine up so more chemical is required to raise the chlorine level

Using stabilised chlorine granules

As shown in the table above, you can adjust the dosage of chlorine granules as required. Depending on whether you’re dosing your pool or spa, or in need of a shock dose, you can measure the amount of granules needed against the volume of water. If you need a little help with the calculations, you can use our handy dosing calculator to get a better idea of the dose of stabilised chlorine granules your pool or spa needs.

You should always be mindful of how using stabilised chlorine granules can affect your pool or spa environment. Regular testing of the water can help catch any irregularities early on, such as an unbalanced pH or problematic alkalinity.

You can read over the stabilised chlorine granules safety sheet, found under the "Product attachment" tab of each relevant product,  to get a full understanding of what issues can occur if the chemicals aren’t handled correctly. There are chemicals you can get to remedy these issues, which are available as part of our chemical starter kits if you need the full suite of pool chemicals.

We have all your pool chemical needs and queries covered

Whether you’re just in need of stabilised chlorine granules or want a wider range of chemicals to maintain your pool, you can rely on us to get them to you. Plus, if you spend over £75 on an order you will qualify for free next-day mainland UK delivery.

For any questions you might have about the required chemicals for your pool or spa, you can get in touch on 0800 358 6140 or via


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