adesalvo,

I'd like to make a comment here. You keep worrying about a possible algae bloom when your FC floats down to 0 and you are wanting to add Borax to help prevent the algae when this happens. I believe you are loosing sight of the big picture here. When your FC gets down to 0, what is sanitizing your pool?

For your kids sake, keep the FC up and don't worry about adding Borax as an algaecide until you get a handle on the chemistry of your pool. It really is not that complicated and you appear to have a good start. Also, though a SWG makes adding chlorine manually a less frequent chore, it is NOT a "turn it on and forget it" solution.

Dave