I usually checked Cl every three days, but checking more frequently until you get the hang of your pool is a good idea. Usually CYA, Ca and Alk don't move much, unless you've been getting torrential rains. Every month is fine, I usually check every 2 or so. It just kinda depends on how much rain i've been pumping out. If I pump out very little, I generally don't worry about those last three much.

Michael