Treat A Green Pool

Getting Rid of Algae with Chlorine Shock

Chlorine is a very effective sanitizer for water and when you maintain a swimming pool with 3ppm (parts per million) of chlorine, it will inhibit algae from growing. However, if you let the chlorine drop, even for a day, you might be left with an algae outbreak, which can turn your water green.
The good news is, chlorine can also destroy algae; you just need to boost the levels and the fastest way is to use chlorine pool shock with a main active ingredient of calcium hypochlorite.

How to Shock Your Swimming Pool with Fi-Clor Superfast Granules

To properly and effectively shock your pool you will need to wait till dusk or night time to do it. Since the chlorine in the shock is unstabilized the sun will burn it off much faster than regular stabilized chlorine so shocking during the day will not be as effective.
One kilogram of Fi-Clor Superfast Granules treats 11,000 gallons of pool water. Remember to keep the pool filter and pump running before and after you dose the pool.

Step 1

Calculate the volume of water in the pool in gallons.
Length x Width x Depth (in feet) x 7.48 = gallons

Step 2

Thoroughly brush off any algae that may be clinging to the pool surfaces.

Step 3

Add 1kg per 50m3 (11,000 gals). Broadcast the product evenly over a wide area in the deepest part of the pool. It should only be used when bathing has ceased. For outdoor use, avoid facing the wind when dosing. For heavy algae contamination, double this dose rate may be required.
The goal with using chlorine shock to kill algae is to get your pool to be a cloudy blue or white colour. Blue or white means the algae has been killed. When algae is dead, it turns a gray colour.

Step 4

Now, you‘ll need to run your pump and filter continuously until the water is clear, probably 24 hours, then backwash the filter and vacuum the pool thoroughly.

Step 5

You may want/need to use a pool clarifier, such as Fi-Clor Rapid Clarifier, to aid in the water clearing process; this may take some time depending on the size and ability of your filter system.

To help prevent a recurrence, ensure that free chlorine levels never fall below 1mg/l (ppm) for unstabilised or 2mg/l (ppm) for stabilised chlorine pools.

We would always recommend dosing the pool with a Long Life Algicide to aid algae prevention going forward once the pool is clear.