TFP Expert
LifeTime Supporter
Jun 12, 2009
NW Ohio
If you use a 25 ml sample instead of 10 ml then your precision will be 0.2 ppm. You will want to use two scoops of powder when doing the 25 ml test. However I agree with Marty, it's not necessary and you go through reagents more than twice as quickly.


Gold Supporter
Bronze Supporter
Oct 25, 2017
Ocala, FL
The instructions for the 25 ml is to use 2 scoops, but it doesnt say how much of the powder to use for 10 ml. Ive just been using 2 scoops per 10 ml of water; have I been doing it wrong?