How much for a shock?

75 g per m³ for a standard 5 ppm shock; 150 g per m³ for a 10 ppm algae shock.

Do I have to pre-dissolve?

Yes. Always pre-dissolve in a 10 L bucket of pool water; broadcasting cal-hypo dry can bleach vinyl and stain plaster.

How long until I can swim?

Wait until free chlorine has dropped below 5 ppm; usually 4-12 hours after a shock.

Why no cyanuric acid?

Indoor pools and high-CYA pools need bioavailable chlorine. Cal-hypo gives 100% active chlorine with no stabiliser added.

How long does a 5 kg pack last?

Around 8-10 standard shocks for a 40 m³ pool, longer if used only as an emergency oxidiser.

Can I use it in vinyl pools?

Yes, provided you pre-dissolve and pour the clear solution; never tip undissolved sediment in.

What is the active ingredient?

Calcium hypochlorite at 65% available chlorine, unstabilised.

How does it raise pH?

Hypochlorite ion combines with water to give hydroxide; cal-hypo dissolves alkaline at around pH 11.

Why is it incompatible with TCCA?

Cal-hypo is alkaline and oxidising; TCCA is acidic and chlorinated. Mixed dry they can ignite.

pH likely spiked; drop with pH Minus and run filtration 12 hours.

Switch to SDIC for routine; partial drain if above 400 ppm.

Cal-hypo is unstabilised and faster but pH-raising; SDIC is stabilised, pH-neutral and gentler. Use cal-hypo for shocks, SDIC for routine.

Cal-hypo vs liquid chlorine?

Cal-hypo is storable for months and easy to ship; liquid chlorine decays in storage but is cheaper per active ppm. Choose cal-hypo for low usage, liquid for daily plant rooms.

Pool Calcium Hypochlorite Granules - Unstabilised Shock Sanitiser

Name: Pool Calcium Hypochlorite Granules - Unstabilised Shock Sanitiser
Brand: ClearSpa
SKU: ps-3
Availability: InStock
Rating: 5.0 (6 reviews)

Unstabilised calcium hypochlorite granules at 65% available chlorine. The fastest hard-hitting pool chlorine for shocks, indoor pools and over-stabilised water where SDIC has stopped working.

Adds 1 ppm of free chlorine per 15 g per m³.
No cyanuric acid, ideal for indoor pools and pools with high CYA.
Hits algae, biofilms and chloramines fast at shock concentrations.
Dissolves in 1-2 minutes when pre-dissolved correctly.
Raises pH and adds calcium hardness as a side effect.