Calcium Hypochlorite Granules 68% Dedusted – Drinking Water Sterilisation, Pool Shock, Disinfection

Professional-grade Calcium Hypochlorite Granules 68% (unstabilised chlorine) designed for drinking water treatment, pool treatment, and disinfection. Dedusted for reduced dust during handling and fast dissolution, this high-purity product delivers reliable chlorine release without stabiliser, making it suitable for controlled water treatment applications. Manufacturer declares conformity with EN 900 for drinking water treatment.

Key Features

• 68% average available chlorine (minimum 65% at manufacture) for powerful sanitisation

• Unstabilised (no cyanuric acid) – suitable for controlled potable water treatment when applicable requirements are met

• Dedusted granules for reduced dust during handling

• Fast-dissolving formula with minimal insoluble residue (maximum 3% according to manufacturer)

Uses

• Drinking water treatment (professional & controlled systems)

• Swimming pool shock and maintenance chlorination

• Spa and hot tub water treatment (subject to equipment compatibility and product authorisation)

• Surface and equipment disinfection (where authorised)

• Commercial water hygiene and treatment

📋 Product Details

Weight: 250g / 1kg / 2kg
Grade: Average 68%, minimum 65% available chlorine at manufacture
Form: Dedusted granules
pH (10 g/L): 10.5–11.5 (verify against batch specification)
Solubility: Fast-dissolving granules; numerical solubility not confirmed in the manufacturer's supplied specification
Standard: EN 900 (manufacturer-declared conformity)

5 Main Uses – Step by Step (Detailed Professional Instructions)

1. Drinking Water Sterilisation (Potable Water Treatment)

⚠️ CRITICAL: Never add granules directly to drinking water intended for immediate consumption. Use an appropriately controlled treatment process.

Step 1: Pre-filter Water (if needed)

• If water is cloudy, remove suspended particles using suitable filtration

• Suspended solids and organic contamination reduce chlorine effectiveness

Step 2: Prepare Stock Chlorine Solution

• Weigh 1 gram calcium hypochlorite

• Add to 1 litre clean water in a clean, dedicated chemical-resistant container

• Add water first, then chemical

• Stir for at least 15 minutes following the manufacturer's preparation instructions

• This produces a theoretical stock concentration of approximately 650–680 mg/L available chlorine, depending on actual product strength

Step 3: Dose Drinking Water

• The amount required depends on water quality, initial chlorine demand and the required final residual

• A 1 g/L stock solution contains approximately 0.65–0.68 mg available chlorine per ml

• For calculation reference only, adding 1 ml of stock solution to 1 litre of water gives a theoretical initial chlorine addition of approximately 0.65–0.68 mg/L

• Actual dosing must be determined through appropriate water testing and an approved treatment procedure

Step 4: Contact Time

• Allow sufficient contact time according to the applicable drinking water treatment procedure

• A commonly referenced operational residual is 0.2–0.5 mg/L free chlorine after at least 30 minutes, under suitable water conditions

• The required initial dose may be higher because chlorine is consumed by contaminants

Step 5: Verification

• Measure free chlorine residual using a suitable chlorine test kit or calibrated testing equipment

• Check that treated water meets applicable drinking water quality requirements

• Do not rely on chlorine smell as evidence of effective disinfection

• If the residual is insufficient, reassess treatment according to the approved procedure

Step 6: Storage After Treatment

• Keep treated water in clean, suitable, covered containers

• Protect from contamination and direct sunlight

• Check residual chlorine where storage conditions or duration require it

Safety:

• Do not overdose

• Never mix with acids (toxic chlorine gas risk)

• Concentrated product is harmful if swallowed and causes severe skin burns and eye damage

• Drinking water treatment must comply with applicable UK requirements

2. Swimming Pool Shock Treatment

Step 1: Test Water

• Manufacturer-recommended pH: 7.0–7.4, subject to local requirements

• Ensure filtration system is operational

• Measure existing free chlorine before treatment

Step 2: Calculate Dose

• Example shock treatment calculation: 10–15 g per m³ (1,000 litres)

• This provides a theoretical increase of approximately 6.8–10.2 mg/L available chlorine at 68% product strength

• Example:

  • 10,000 L pool → 100–150 g

  • 20,000 L pool → 200–300 g

  • 50,000 L pool → 500–750 g

These quantities are illustrative calculations, not fixed shock-treatment doses. Adjust according to existing chlorine levels, water condition and the applicable pool treatment procedure.

Step 3: Pre-dissolve

• Use a clean, dedicated container

• Fill with the required quantity of clean water first

• Slowly add the measured granules while stirring

• Continue mixing for at least 15 minutes, following the manufacturer's instructions

Step 4: Apply to Pool

• Apply using the approved pool chlorination procedure

• Ensure the circulation and filtration systems are operating

• Do NOT add when swimmers are present

Step 5: Circulation

• Keep the filtration and circulation systems operating during treatment

• Allow sufficient circulation time for uniform chlorine distribution

• Follow the pool's operating procedure for treatment duration

Step 6: Re-test Before Use

• Measure free chlorine and pH before reopening the pool

• Manufacturer's recommended normal chlorine level: 1–3 mg/L

• Do not allow swimming until chlorine levels comply with applicable operating limits

Safety:

• Never mix with other pool chemicals

• Add chemical to water, not water to chemical

• Never use contaminated buckets, feeders or dosing equipment

3. Routine Pool Chlorination (Maintenance)

Step 1: Daily Dose Calculation

• Manufacturer's typical daily consumption: 500 g – 1 kg per 100 m³ per day

• Equivalent quantities:

  • 10,000 L → 50–100 g daily

  • 20,000 L → 100–200 g daily

  • 50,000 L → 250–500 g daily

  • 100,000 L → 500 g–1 kg daily

These are typical consumption estimates rather than fixed daily dosing requirements.

Step 2: Adjust for Conditions

• Chlorine consumption may increase during:

  • Hot and sunny weather

  • Heavy pool usage

  • Increased organic contamination

• Always adjust the dose according to measured free chlorine levels

Step 3: Application

• Prepare a solution according to the manufacturer's instructions or use a suitable approved dosing system

• Do not introduce granules into a skimmer or feeder containing other chemicals

• Add gradually using the appropriate treatment procedure with circulation running

Step 4: Monitor Levels

• Maintain:

  • Free chlorine: 1–3 mg/L, as recommended by the manufacturer unless local requirements specify otherwise

  • pH: 7.0–7.4, subject to local requirements

• Test regularly and adjust treatment as required

Step 5: Balance Water Chemistry

• Total alkalinity: 60–120 mg/L

• Monitor calcium hardness and other relevant pool chemistry parameters

• Maintain appropriate water balance to reduce scaling and equipment problems

4. Spa / Hot Tub Treatment

Step 1: Measure Water Volume

• Example: 1,000 litres spa

• Confirm that calcium hypochlorite is suitable for the spa equipment and authorised for the intended application

Step 2: Dose Calculation

• For 1,000 litres, theoretical chlorine increases at 68% available chlorine are:

  • 2 grams → 1.36 mg/L

  • 3 grams → 2.04 mg/L

  • 4 grams → 2.72 mg/L

  • 5 grams → 3.40 mg/L

These values show theoretical chlorine additions, not universal recommended doses. Actual dosing depends on existing chlorine and chlorine demand.

Step 3: Pre-dissolve

• Where permitted by the spa and chemical manufacturer's instructions, prepare the required chlorine solution in a clean, dedicated container

• Always add granules to water, never water to granules

• Mix according to the manufacturer's preparation procedure

Step 4: Add with Circulation Running

• Follow the spa manufacturer's approved chlorination procedure

• Ensure sufficient circulation for even distribution

• Do not mix with other treatment chemicals

Step 5: Contact Time

• Allow the treatment contact and circulation time required by the approved procedure

• Do not assume that 15–30 minutes is sufficient for every spa treatment

Step 6: Test Before Use

• Check free chlorine and pH using a suitable testing kit

• A commonly used spa free chlorine operating range is 3–5 mg/L, subject to local requirements

• Do not use the spa until all relevant water quality parameters are within the permitted range

Safety:

• Follow spa manufacturer's ventilation and cover instructions during treatment

• Avoid inhaling vapours, fumes or dust

• Use only where product compatibility and authorisation are confirmed

5. Surface & Equipment Disinfection

Step 1: Pre-clean Surface

• Remove dirt and organic matter

• Clean surfaces thoroughly before applying a disinfectant

• Check material compatibility, particularly for metals and chlorine-sensitive materials

Step 2: Prepare Disinfection Solution

• The following are theoretical available chlorine concentrations at 68% product strength:

  • 0.5 g per litre → approximately 340 ppm

  • 1 g per litre → approximately 680 ppm

  • 1.5 g per litre → approximately 1,020 ppm

  • 2 g per litre → approximately 1,360 ppm

For reference, the manufacturer's preparation table specifies approximately 1.5 g per litre for a 0.1% (1,000 ppm) available chlorine solution.

These figures are concentration calculations, not approved surface disinfection doses. Select the concentration according to the applicable product authorisation and validated disinfection procedure.

Step 3: Apply Solution

• Use an application method approved for the intended surface and disinfection process

• Suitable methods may include wiping or immersion where specifically authorised

• Avoid creating airborne chlorine mist

Step 4: Contact Time

• Follow the validated contact time for the intended application

• Required contact time depends on chlorine concentration, surface condition and the target microorganisms

• The manufacturer's supplied technical sheet does not specify a universal 5–10 minute surface disinfection contact time

Step 5: Rinse (if required)

• Rinse surfaces where required by the approved treatment procedure

• Food-contact surfaces may require additional rinsing and verification

• Follow applicable hygiene requirements

Step 6: Air Dry

• Allow surfaces to dry according to the approved procedure

• Prevent recontamination after treatment

Safety:

• Use protective gloves and eye/face protection

• Work in a well-ventilated area

• Never mix chlorine solutions with acids, ammonia or other cleaning chemicals

📈 Other Names

Alternative Names:
Calcium Hypochlorite 68%, Cal Hypo Granules, Chlorine Granules, Drinking Water Chlorine, Pool Shock, Water Purification Chlorine

Keyword-Rich Titles:

• Calcium Hypochlorite Drinking Water Treatment

• Chlorine Granules 68% for Pools & Potable Water

• Cal Hypo Granules for Professional Water Purification

• Pool Shock & Water Disinfection Chlorine Granules

• Unstabilised Chlorine Granules High Strength

❓ FAQs

1. Can I use this for drinking water?
The original manufacturer identifies drinking water treatment as an intended application and declares conformity with EN 900. Use must comply with applicable requirements and be carried out using a controlled, verified treatment process. No universal drinking water dose is provided in the manufacturer's supplied instructions.

2. Why is unstabilised chlorine important?
It contains no cyanuric acid stabiliser. This makes it suitable for applications where unstabilised chlorine is required, including appropriate controlled water treatment systems. Suitability for drinking water also depends on product conformity and applicable treatment requirements.

3. Can I add granules directly to water?
For preparing chlorine stock solutions, always add granules slowly to water in a clean, dedicated container, never water onto dry granules. For pools and other treatment systems, follow the manufacturer's approved application procedure.

4. What are the main hazards?
It is a strong oxidiser, causes severe skin burns and eye damage, is harmful if swallowed, and must never be mixed with acids or other incompatible chemicals. Contact with acids releases toxic chlorine gas.

5. How much Calcium Hypochlorite should I use for my swimming pool?
The manufacturer states typical daily consumption of 500g–1kg per 100m³ of pool water. Actual dosing depends on pool volume, existing chlorine levels, water quality and usage. Always test before and after treatment.

6. What pack sizes are available?
HD Chemicals supplies Calcium Hypochlorite Granules 68% in 250g, 1kg and 2kg packs.