How to Treat Dank Water in a Pool

Diagnose your pool problem so you can treat it correctly. Algae that turns pool water dank may be black, green or mustard-colored. Each requires a slightly different chemical process.

Clean out your pool as much as possible before treatment. Vacuum your pool floor and liner with your pool vacuum, and skim particles from the water with your skimmer.

Treat your pool for your type of algae. A 60 percent non-copper algaecide kills green algae, while a mustard algae algaecide both black and mustard algae. Follow the directions to mix and apply your algaecide. Base the treatment dosage on the water capacity of your pool to ensure that the algae is killed. After treating, wait the recommended time for the algaecide to work.

Shock your pool to help restore the water quality. To shock a pool, measure 2 pounds of shock chemicals, such as calcium hypochlorite, per 10,000 gallons of water. Dissolve the shock chemicals in water, using a bucket to mix them. Then pour the treatment into your pool directly. This is more than your typical pool shock and it will help restore the health of your pool.

Check your pool pH and alkalinity post-shock to make sure they're in the right place to prevent future algae growth. Pool pH should range from 7.2 to 7.8. Higher levels allow algal growth and lower levels irritate skin. Alkanity can range from 80 to 120 parts per million (ppm). Adjust these if necessary, adding dry acid to raise alkalinity or pH increaser or decreaser to adjust pH.