FAS-DPD remains pink, won't turn clear

[Cetanorak]

For weeks, I've been maintaining FC levels between roughly 3-7ppm as my CYA has shifted from 50 to 40. Suddenly this evening, I'm attempting to run the FAS-DPD and after adding the 870 powder I am adding 20-25 drops of 871 and the 10mL solution is still remaining a dark pink. Is this a sign that my reagents are suddenly expired...I just can't make sense of this sudden change.

It hasn't been a year since I purchased the TF-Pro kit however I am nearly at the bottom of the 870 powder. Does the fine dust that settles at the bottom sometimes give false readings for any reason?

Thank you!

 

[JamesW]

Are you sure that it is the right bottle?

 

[Brian PacNW]

What is the stamped Best By date on the powder and the 871?

Perhaps try going to 5 mL of water with 1 scoop of powder, then 1 drop of 871 is equivalent to 1 ppm.