Let it hover there.

Also, please test both FC and TC, and report those results. As far as trying to hold the chlorine stable, I wouldn't worry too much about that -- you can't really do so till you get your algae and chemistry issues resolved. Instead add some bleach during the day, to keep it above 2, but add 6 - 8 gallon doses in the evening. Keep doing that till you can hold high chlorine levels overnight.

Ben