DPD tests

[mrhappye]

I am new to this forum and have been reading many of the posts.
I have tested chlorine levels with DPD drops (Taylor) and DPD tablets (No. 1 and 3) that I have - I don't have an FAS test kit yet. The drops are fresh bottles.
With the DPD drops, I get a much lower reading than the tablets. The tabs can have a FC 3 and the drops 1. No CC. I brought a sample over to local pool store that uses the Waterlink Express and their value was closer to the DPD tablet reading. Anyone know why there is a discrepancy between the tests?

 

[JasonLion]

It is possible that your DPD drops have gone bad. If everything was working correctly they should agree with each other more closely than that.

 

[mrhappye]

That was my first thought. Brand new bottles from the pool store. I don't know how long they have been there, but I assume they are from a new lot this season. Maybe I can contact Taylor with the lot no. I tend to trust the tablets more.
Thanx.