Carl does add bleach via the skimmer, but he doesn't use trichlor pucks. The danger with adding bleach (or liquid chlorine) through the skimmer with trichlor in the feeder is the possibility that the chlorine will react with the trichlor before it's sufficiently mixed with water, and cause a chemical reaction that is explosive. I would stick with adding it "over the side", but if you will pour it slowly in front of your return, then the jet from the return will disperse the chlorine before it has a chance to eat up your liner.

Janet