Keep the chlorine at 15 as consistently as you can. What kind of filter do you have and what size is the pump? If you tested the pH when the chlorine was high, you may have gotten a falsely high reading. Retest pH when the chlorine is below 5ppm unless you have a Taylor K-2006. In that case, you can trust the pH test with chlorine readings up to 15ppm. By the way, what kind of test kit do you have?

Is there actual debris for the Rover to clean out? If so, it won't hurt to put the Rover in. Run the pump 24/7.