Taylor Test kit 2006c

I just got my new test kit and have a question on the relationship between the amount of DPD powder added to a chlorine test sample. The test allows for a 0.2 ppm or a 0.5 ppm titration depending whether the pool water sample is 25 ml or 10 ml. Regardless of the sample size it still indicates to add two scoops of the DPD powder in order to turn the sample pink.

According to this procedure, the amount of DPD powder added appears to be unrelated to the sample size which, to me, seems intuitively incorrect.

What am I missing?

thanks in advance



106,000 litre inground vinyl with solar
Saskatchewan, Canada

Actually, if one scoop turns the sample pink, then you don't need to use two. I always just use one scoop.

it is a tritreation test. DPD is merely the indicator. The titrant will react with the FC in the water (or the CC if you are doint that part) and once the chlorine has reacted with the titrant then it is no longer available to react with the DPD and turn it pink. sometimes half a scoop is all that is needed witha really fresh DPD powder if the chlorine levels are not too high!

Makes sense.

thanks