If I compare the test results using the 25mL sample and the 10mL sample they are not the same. For example the 25mL sample give a result of 8ppm (16 drops x 0.5) and the 10mL sample gives 12.5ppm (10 x 1.125). I prefer to use the 25mL sample because it's easier to swirl but i can save on drops by using the 10mL sample when anticipating high bromine levels.
Has anyone else seen these discrepancies? Also, I would have thought you'd need to add less R-0870 DPD powder in the 10mL sample than the two scoops that are added to the 25mL? But it doesn't say anything about this in the instructions.