I've got something, created partly with you in mind:
http://pool9.net/pf-hist-form
with results here:
http://pool9.net/pf-hist-chart
+ Get a cheap OTO / phenol red kit. It won't bleach out, at any chlorine level, and will be useful even after you have the K2006 for quick checks.

+ Tell me what % bleach you are using.