How much to add for a 5 ppm shock?

Approximately 7.5 g per 1000 L of water, pre-dissolved in 10 L of warm water before adding.

Yes. Each 1 ppm of chlorine added with calcium hypochlorite lifts pH by about 0.05 units.

How long until I can bathe?

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

How long does a 5 kg pack last?

Around 30-50 standard pool shocks for a 30 m3 pool.

Is it safe for vinyl liners?

Yes, when fully pre-dissolved. Never broadcast dry granules onto a vinyl liner.

Can I use it in a hot tub?

Only as a periodic CYA reset shock. Daily dosing in hot tubs should use SDIC, TCCA tablets or bromine.

What is the active ingredient?

Calcium hypochlorite (Ca(OCl)2) at >= 65% available chlorine.

Why does it raise calcium?

Each calcium hypochlorite molecule releases one calcium ion alongside two chlorines.

Why use unstabilised chlorine?

Stabilised chlorine builds CYA. Calcium hypochlorite delivers chlorine without CYA, ideal for indoor pools and CYA-saturated water.

Cloudy water after shock?

Granules added dry or pH out of band. Filter for 24 hours and dose clarifier.

pH spike after shock?

Dose pH minus per the table to bring pH back to 7.4.

Clean filter overnight, vacuum dead algae, dose clarifier.

Calcium hypo vs SDIC?

Calcium hypochlorite is unstabilised, alkaline and adds calcium. SDIC is stabilised, pH-neutral and adds CYA.

Calcium hypo vs liquid bleach?

Both are unstabilised chlorine. Granules are easier to store and dose; liquid bleach is faster to dose but harder to handle.

Spa Calcium Hypochlorite Granules

Name: Spa Calcium Hypochlorite Granules
Brand: ClearSpa
SKU: wst-3
Availability: InStock
Rating: 4.5 (6 reviews)

Fast unstabilised chlorine shock for pools and indoor spas. 65% calcium hypochlorite granules deliver a 5-10 ppm chlorine kick in minutes, with no cyanuric acid build-up.

Adds 1 ppm of free chlorine per 1.5 g per 1000 L.
Burns through algae blooms and high combined chlorine.
Adds calcium hardness (~7 ppm per 5 g per 1000 L).
Free of cyanuric acid; ideal for indoor pools.
Suitable for periodic super-chlorination of spas with high CYA.