To remove algae from a pool, follow a step-by-step process of cleaning, shocking, filtering, and vacuuming. First, clear debris, brush the walls and floor vigorously to loosen the algae, and clean your filter. Next, test the water and balance the pH (7.2–7.6) and alkalinity (80–120 ppm) before shocking the pool with a heavy dose of chlorine. [1, 2, 3, 4]
1. Clean and Brush
- Skim: Use a pool net to remove any leaves or loose debris from the water.
- Brush: Thoroughly brush the pool walls, steps, and floor with a stiff brush to break up the protective slime layer of the algae and get it suspended in the water.
- Clean the Filter: Backwash or rinse your pool filter so it doesn't get immediately clogged during the treatment process. [1, 2, 3]
2. Balance the Water
Test your pool water using a reliable Test Kit and adjust the levels so your chlorine can work effectively. [1, 2]
- pH Level: Aim for 7.2 - 7.6.
- Alkalinity: Aim for 80 - 120 ppm. [1]
3. Shock the Pool
"Shocking" means super-chlorinating the water to kill the algae. A regular maintenance dose will not be enough to fix a severe bloom. [1]
- Dosage: Use a double, triple, or quadruple dose of shock depending on the severity of the algae. For light green water, use a double dose (2 lbs of shock per 10,000 gallons). For dark green or black algae, use a triple or quadruple dose. [1, 2]
- Shock Type: Calcium hypochlorite is the strongest choice, but liquid chlorine or dichlor is recommended for saltwater or fiberglass pools to prevent calcium buildup. [1]
- Timing: Add the shock at dusk so the sun does not burn off the chlorine before it has time to work. [1]
4. Filter and Vacuum
- Run the Pump: Leave your pool filter running on high for 24 - 48 hours straight.
- Vacuum: Once the algae are dead, the water will turn a cloudy grey or blue, and the dead algae will settle on the floor. Vacuum your pool to waste to physically remove the dead cells from the water.
- Final Clarification: Use a Pool Clarifier to help the filter catch any remaining microscopic particles. [1, 2]
