Pool store refused to test my water...

[waterbear]

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.
Edit: Whoops! My brain locked up too! I meant to say above that OTO only tests total chlorine! I was thinking that when I typed the last line above!

[Carolina]

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)!