I don't understand the chemistry of the chlorine/CYA ratio, but wonder if there is any reason to maintain a higher or lower CYA concentration. Is there any advantage to maintaining say 40 ppm CYA over a 20 ppm concentration? The lower CYA number would require a lower chlorine number which would let my liquidator go longer between refilling and use less chlorine. I've been keeping the CYA at 40 ppm but not really sure if there is any good reason why it should be 40 instead of 20.