Dave and Watermom are right--don't use the 25ml sample, use the 10ml. In ten years, I think I've used the 25 ml once.

When they say .2 and .5, (and this is gonna sound crazy but it's not) every FIVE drops in the 25ml sample is 1ppm of FC, and every TWO drops in the 10ml sample is 1ppm of FC. (5drops to 1ppm means each drop is .2, 2 drops to 1ppm means each drop is .5)

Carl