Ph color not on the scale

I have an inground pool with white plaster walls that holds about 15,500 gallons. I recently had a very bad green algae problem. I've shocked it enough that the algae is no longer an issue. The water is currently cloudy and I've hosed off the filters several times the past couple of days. There is a lot of chlorine in the pool due to the intense shocking I've done. I'm having problems getting the Ph balanced though. I'm checking the Ph using Aqua Chem products and the associated color scale. However, the color doesn't match anything remotely close to any of the colors on the scale. The color I'm getting is dark blue/purple. I'm sure that isn't good, but I don't know if I should add acid or soda ash. :confused:

LTCKLP2000

I assume that your Cl levels are still very high. The pH indicator will give false readings with high Cl levels. It actually converts to a different indicator that tests a much lower pH range and the color that you are seeing just means that the pH is somewhere above 6.8. You need to let the Cl levels drop to below about 10 ppm and then retest your pH.

Thank you very much. I'll do that.

LTCKLP2000