Question about the "extra drop" rule

[tcm0116]

Does the "extra drop" rule apply to the FAS-DPD test? I've noticed that if I add the extra drop when testing the FC, then my CC will be 0. However, if I don't add the extra drop when testing FC, then my CC is 0.5.

Because the limit for CC is 0.5, this distinction could be important if the CC is truly above 0.5 and the extra drop during the FC test artificially lowers the CC reading by 0.5.

Thanks!

 

[ping]

I stop adding drops after the pink is gone and the water is colorless, I do not add another drop. Taylor's instructions say to do the same, http://www.taylortechnologies.com/products_instructions.asp?Type=Number&Number=5217.

 

[pwrstrk]

I stop adding drops after the pink is gone and the water is colorless, I do not add another drop. Taylor's instructions say to do the same, http://www.taylortechnologies.com/products_instructions.asp?Type=Number&Number=5217.

I do the same thing. I can tell the water is clear without adding the extra drop. Went this whole season with zero CC's.

 

[JasonLion]

Ideally you don't want to add an extra drop when doing the FC portion of the FAS-DPD test. However, if there is any confusion about the pink just being mostly gone vs totally gone you may need to use one just to be sure. The extra drop, if any, does count towards CC, but only if there is any CC. Novices have been known to get this wrong in both directions, i.e. using too many drops in the FC portion lowers the CC reading, and likewise using too few drops in the FC portion raises the apparent CC level.