Quote Originally Posted by waterbear View Post
Carolina,
They are probably tesing with DPD and not OTO. OTO (turns yellow) doesn't bleach out, which is it's one great plus. DPD (turns red) does. It will only test TC however.
Yes, you are right, they do use the DPD test. I have the OTO test at home and I got confused for a moment (sorry - mommy brain)!