Pool Rapid Shock Treatment - Combined Sanitise & Clarify

Fast-acting cal-hypo shock tablets for spot-treating problem zones. 200 g unstabilised tablets dropped into the skimmer or feeder for a controlled overnight shock without weighing granules.

• Releases 10-12 ppm of free chlorine over 2-3 hours per tablet.
• Targets specific problem zones via skimmer feed.
• Adds no cyanuric acid, ideal for high-CYA pools.
• Cleaner to handle than granules; no weighing or pre-dissolving.
• Pairs with a weekly granule shock for full-pool oxidation.

Sizes and prices

• 5kg: £48.00
• 10kg: £94.75
• 25kg: £235.00

When you need it

• You are seeing localised algae near a return or shaded corner.
• You want an overnight shock without measuring out granules.
• Cyanuric acid is at its upper limit and SDIC shocks no longer work.
• Bather load was heavy and you need a controlled chlorine spike.
• You need to break a chloramine reading without a manual broadcast shock.

How to use

1. Confirm pH 7.2-7.6 before shocking.
2. Place 1 tablet per 25-30 m³ in the skimmer basket or a chemical feeder.
3. Run filtration overnight, ideally 12 hours.
4. Check free chlorine in the morning; should be 5-10 ppm.
5. Allow chlorine to drop to under 5 ppm before bathing.
6. Repeat weekly through summer or as needed for problem zones.

Dosing guide

Tablets are pre-measured 200 g cal-hypo. Use 1 tablet per 25-30 m³ for a 5-7 ppm overnight shock; 2 tablets for an algae shock.

• For 20 m³, add 1 tablet to reach 5-7 ppm overnight shock.
• For 40 m³, add 1-2 tablets to reach 5-7 ppm overnight shock.
• For 60 m³, add 2 tablets to reach 5-7 ppm overnight shock.
• For 40 m³, add 3 tablets to reach Algae shock.
• For 20 m³, add 1 tablet (let dwell) to reach Spot treat single zone.

How it works

Calcium hypochlorite at 65% available chlorine compressed into 200 g rapid-dissolving tablets, formatted for skimmer or feeder dosing.

Each tablet erodes over 2-3 hours under skimmer flow, releasing hypochlorous acid (HOCl) and unstabilised free chlorine. The slow-erosion profile gives a more even shock than dumping granules.

Spot shocks are awkward with granules; tablets give controlled overnight chlorination without weighing, pre-dissolving or risking liner bleach.

Frequently asked questions

How long does the shock take?

2-3 hours per tablet to fully erode; leave overnight for maximum effect.

How much for my pool?

1 tablet per 25-30 m³ for routine shocks; 2-3 tablets for algae blooms.

Can I bathe straight after?

No. Wait until free chlorine drops below 5 ppm; usually morning after overnight shock.

Pack sizes?

1 kg (5 tablets) and 5 kg (25 tablets).

Why not just use granules?

Tablets save weighing, pre-dissolving and the mess of bucket dosing. Cleaner for skimmer feed.

Will it raise CYA?

No. Unstabilised cal-hypo, no cyanuric acid added.

What is the active ingredient?

Calcium hypochlorite at 65% available chlorine, unstabilised, in 200 g compressed tablets.

Why does it raise pH?

Cal-hypo dissolves alkaline; expect 0.2-0.3 lift per shock.

Tablet vanished but chlorine low?

Demand exceeded dose; follow up with granule shock and check for biofilm.

Cloudy water?

pH spiked; drop to 7.2 with pH Minus and dose clarifier.

Rapid shock tablets vs granule shock?

Tablets are slower, controlled and tidy; granules are faster and stronger but messier. Use tablets for skimmer feed, granules for whole-pool emergencies.

Rapid shock vs TCCA tablets?

Rapid shock is unstabilised cal-hypo for short shocks; TCCA is stabilised slow-feed for routine sanitising. Different jobs.