I know this has been debated before but just want to get a clearer answer in my mind. Right now I have a CYA of 70ppm and keep my FC at a 8ppm target (Use the TF-100). I want to use less of the regent so instead of 10ml I want to use 5ml of water sample. Can I use 5ml and count each drop as 1ppm? I tested until it was slightly pink still and figured the reading was slightly highier than that value. The next drop turned it clear. Thanks in advance!