How to Get Rid of Mustard Algae in the Swimming Pool

Yellow mustard algae in the pool can cause allergic reactions.

Mustard algae is a form of green algae that is rare but dangerous in pools. Mustard algae resembles dirt or sand at the bottom of the pool. Although it can be cleaned away with a brush or vacuum, the algae will soon return with a vengeance. Prevent mustard algae by cleaning the pool regularly and keeping the pH level of the water between 7.4 and 7.6.

Things You'll Need

• pH strips
• Brush
• Oxidizer
• Algaecide
• Pool vacuum

Instructions

1. Dip a pH testing strip in the water and compare the color to the pH test chart. Adjust the pH of the pool to between 7.0 and 7.2 by adding chlorine according to the instructions on the packaging.

2. Brush the walls and the floor of the pool with a pool brush to loosen the algae. Let the algae settle, then vacuum the algae out using your pool vacuum. Backwash the filter after this process.

3. Add a package of oxidizer to the pool to increase the oxygen in the water and fight against the algae. Apply the package of oxidizer according to the number of gallons of water in your pool and the instructions on the label.

4. Add a mustard algae algaecide to the pool eight hours after the oxidizer is added to the water. Follow the instructions on the algaecide label for application.

5. Toss the brushes and vacuum and any other equipment you used to clean the algae into the pool to kill off any lingering algae.

6. Vacuum the pool again in two days and test the water pH for safety.

References

• Clean-Pool-and-Spa.com: Yellow Algae

Resources

• Arthurs Pools: Mustard Algae Prevention and Treatment
• Pool Breeze: Pool Care Guide