Quote Originally Posted by Themadczar View Post
Not sure I'm following you... Do you mean I should read the oto test after 10 minutes and that should give a tc reading that will match immediate dpd results?
If I got that correct, then after waiting 10 min, the oto test was definitely darker yellow than the 3ppm mark (the highest on my test) but not by much... I would think 20ppm or so would be much darker yellow or brown, but maybe I'm wrong.