Recognise the type
- Green / blue-green: the common free-floating bloom, often after heat, rain or low chlorine.
- Mustard (yellow): clings to shaded walls and steps and brushes off easily but returns fast.
- Black: dark spots that root into plaster and grout and need scrubbing as well as treatment.
Step-by-step clearing routine
- Test and balance first. Bring pH to 7.2–7.6; chlorine and algaecide do little in unbalanced water. See fixing pH.
- Brush every surface to break up the bloom, especially steps, corners and shaded walls.
- Dose algaecide. Pool Cide is a chlorine-free QAC algaecide for green, blue-green, mustard and black algae. Dose 1 litre per 1,00,000 litres, once or twice weekly. Dose after 4 pm, pour along the pool sides and keep the pool out of use for 6–8 hours.
- Keep chlorine up. Maintain a regular Pool Chlor TCCA 90 routine: 1–1.5 kg per 1,00,000 litres at least once a fortnight.
- Run the filter continuously until the water clears; if dead algae leaves the water cloudy, follow with a clarifier (see clearing cloudy water).
- Brush and vacuum the settled debris out the next day.
Pool Cide is non-foaming, doesn't sting, and is safe with all pool filters. Copper sulphate crystals (900 g pack) are also used for algae control in pools, ponds and fountains at about 60 g per 50,000 litres.
Keep algae from returning
- Dose chlorine on schedule, not only after problems appear.
- Keep pH in range and filtration running long enough each day.
- Dose algaecide weekly in hot, humid or heavily used periods.
- Clean the skimmer and pre-filter baskets regularly.
Common questions
How do I get rid of green algae in my swimming pool?
Balance the pH to 7.2 to 7.6, brush the surfaces, dose an algaecide such as Chemtex Pool Cide at 1 litre per 1,00,000 litres, keep chlorine up and run the filter until the water clears.
When should I add algaecide to my pool?
After 4 pm, so sunlight does not break it down. Pour along the pool sides and keep the pool out of use for 6 to 8 hours.
How often should I dose algaecide?
Once or twice a week at 1 litre per 1,00,000 litres of pool water, depending on weather and use.
Is algaecide safe for pool filters?
Chemtex Pool Cide is non-foaming and safe with all pool filters.
Why does my pool turn green so quickly?
Heat, rain, low chlorine, poor circulation and pH drift all feed algae. Regular chlorine dosing and a weekly algaecide dose reduce the risk.
Products used in this guide
Need help with dosing for a hotel, club or society pool? Call +91-90739-38217 or contact us. Delivery across India, dispatched within 24 working hours.