Thanks for your input. Have only had the pool for ten days. The previous owners stocked the auto chlorine feeder with some kind of "puck" thingy. Is there some kind of conversion ratio of thingy to bleach? Don't I need the stabilizer to keep the CL from burning up in the sun? (I live in Houston). I retested the Ca and it came in at 430, still high. Is the CYA making the Ca high? (plaster liner). My concern is changing the chemicals and inviting problems which I don't see now. If I just keep the Cl in range won't that keep the wee beasties away? Thanks.