We changed the sand 7/1/2011. No combined chlorine most of the time, but I still can't get a good free chlorine reading. I did have a combined chlorine once of .5 I'm averaging putting 12 - 24 ozs of 65% cal-hypo every night.
My readings tonight were
fcl 1.5
tcl 1.5
ccl 0
ph 8.0
alk 140
cya 60

I put 12 ozs. cal hypo and 20 ozs. dry acid to lower ph

Should I be using so much every day?
The water is great! No smell, beautifully clear!