I tested the pool tonight for Cl with both the Taylor Quick Test (colored block) and with the FAS-DPD test in the TF-100. The results were vastly different.
Qucik Test - Barely 2
FAS-DPD - 4
I just recently bought some replacement reagent for the qucik test from a pool store. Could it be the R-0600 is somehow out of date or not as effective. Results with the original reagent were always very close to the other test. Also, if I let it sit for a minute or two, it gets a little darker.