With a vinyl liner and 0 CYA, if you'll just up your chlorine to 12-15 ppm, re-test and add whatever amount is necessary to come back up to the 12-15 level 2-3 times daily, keep your pump running, then you should start to see your cc coming down. When it comes down to zero, then let your cl drift back down and add your CYA.

You can use trichlor pucks in your feeder if you add your liquid chlorine into the pool itself instead of the skimmer---once it's mixed with water, then you shouldn't have a problem. I add my bleach into the return stream with my feeder running on a regular basis.

Janet