Yeah, bring the Cl right back up to 15ppm every single chance you get. Of course, to do that, you must test first so you add the right amount.

It looks like your still working with waaaay too much CC. Make sure you are getting your Cl to shock levels.

If that CC reading is accurate (double check your testing method) you could easily go to 18ppm because the Cl consumption starts immediately. In fact, I would guess that if you dose only to 15, you never get there.

That said, I am fairly aggressive with Cl while others are more conservative. My experience has indicated that a high level of "goo" in the water (which you apparently have) requires a higher dosage than breakpoint to ever get to breakpoint (shock)

(Hmmm, I wonder if that has anything to do with my liner coloring disappearing last week ) I'm Kidding! I'm kidding!