After add akalinity up why is my backwash water consistently blue and a constant sheen almost looks oily on the surface of pool?

- Acid has not been added to pool water prior to adding akalinity up

- Calcium hardness may be too high

- Filter may need cleaning

- Pool may need shocking

When the pH level of the pool is too high, it can cause the water to become cloudy and blue. The higher pH can also irritate skin and eyes. In addition, akalinity up can cause a sheen to form on the pool water.

Solutions:

- Add acid to the pool water to lower the pH level. It is recommended to aim for a pH between 7.2 and 7.6

- Lower the calcium hardness. High levels of calcium can make it difficult for chlorine to kill bacteria. The optimal amount of hardness for pool water is 200 to 400 ppm.

- Clean the filter if necessary. A dirty filter can trap dirt and debris, which can make the pool water look blue.

- Shock the pool to kill any bacteria that may be present. Shocking the pool should be done once a week.