FC Test - Taylor R-0001/R-0002 vs. R-0870/R-0871

[acpie360]

I have both Taylor K-1001 and K-2006 so I tested pH and FC for the same pool water using two different kits. The pH readings were close but the FC differed by 1ppm. Using R-0001/R-0002 with color matching, I get FC = 2.0ppm, while using R-0870/R-0871, I get 3.0ppm (0.2 x 15). Does this mean the R-0001/R-0002 method always "underestimate" FC or it is just simply less accurate (as +/- 1ppm)?

K-1001 was from the previous home owner. All reagents will expire at the end of this year.

 

[Richard320]

The colorblock is never going to be as accurate as the FAS-DPD test. It's too subjective. Even the background color can affect what the eye sees. I don't think you can make a blanket statement that it always under-reads or always over-reports because you're dealing with the human eye and color perception. With the FAS-DPD test even someone who is colorblind can tell tinted versus clear.

 

[LFrankow]

A titration test will always be more accurate then a colour match test. Variables in lighting, differences in seeing different colours etc.

 

[acpie360]

Thanks guys.