Thanks Sherra. I have a vinyl pool, no heater or chlorinators, so I won't be refilling on the calcium supplies. Along this line, Ben's reagent lifespan chart at http://www.poolsolutions.com/kit/ps2...gent_life.html has a row for the PH #1/ R-0004 (pH indicator phenol red) reagent, but makes no reference whatever to either the acid (R-0005) or base (R-0006) demand reagents. Anyone know what the expected life span on these are?