Let me also refer you to the "Can my pool stay home alone for 10 days?" thread since that seems to address your more immediate problem of how to keep the chlorine levels up during your extended absence. The two main ways that were suggested were to use Tri-Chlor tablets in a slow release feeder (plus having the TA and pH higher to start with) or to use liquid chlorine or bleach jugs with small holes punched in them.