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What to do when your pool goes green

Sometimes, no matter how hard you try or how often you maintain your pool, nature manages to gain control and you end up with a algae on the sides of the pool. This occurs more often after thunderstorms and heavy rains, which wreak havoc on the pH of swimming pool water.


How to give your pool a shock treatment

Ninety percent of green water in a swimming pool can be sorted by shock treatment. Before treating your pool with any algaecide products it is recommended that you undertake a shock treatment.

Clean out the pump and weir baskets; backwash for 2 minutes and rinse for 20 seconds. Test and correct the pH level - see video at bottom of this page for details. Shock treat with 3 cups of HTH granular or a sachet of HTH Shock It, following the instructions on the pack. Set the pool on filter for 24 hours. Now backwash the pool for 2 minutes and rinse for 20 seconds.

If the pool water is still green after 48 hours, the water could be overstabilised or there are high levels of metals in the water. Test with an HTH quick test strip and follow the recommended guidelines.


Where there is green algae on the sides of the pool but the water is clear, brushing with a pool brush should take care of this. However, stubborn algae can be removed easily with an algaecide.

HTH Green Algaecide kills green algae on pool walls. The product contains a built-in flocculant to trap fine particles and add sparkle to your pool. Before using HTH Green Algaecide it is important to test the pH of your pool. Use a test kit to run a test on the pool water. The ideal pH should be between 7.2 – 7.6. If the pH is under 7.2, add Alkalinity up. Or for a pH above 7.6, add pool acid. Test again the following morning.

Brush down the walls with a pool brush and then backwash the filter.

In the later afternoon or early evening pour in HTH Green Algaecide and run the pump as usual.

On the following morning, brush down the sides of the pool again with a pool brush.

It's as easy at that...!

Where algae has been left for more than a day or two and still remains in the pool after treatment with HTH Green Algaecide, shock treat the pool water in the early evening with a sachet of HTH Shock It. It is available in 1 and 2 litre bottles at your local Builders Warehouse.

How to test your water the easy way