Jim, I recommend that you not add bleach directly to the skimmer. When you do, relatively undiluted bleach can reach your inline chlorinator and have disasterous results (like an exploding chlorinator). I understand that this can happen even if you empty the chlorinator of pucks and is probably likely if you don't empty it.

On your pump run times, you're probably better off to split your pump runs into two or even three different segments instead of one big twelve hour stint.