Chem_Geek: Heeeeeeelllllllpppppppp!!!

[LexPlayer]

The chemical in most chlorine removers is sodium thiosulfate (photographers hypo).
Your pH was NOT high, that was interference from your high chlorine levels. Never adjust pH when chlorine levels are high since that will always cause your pH to read high falsely.

I assume your test strips are testing free chorine. OTO tests total chlorine and it is very possible the TC is much higher than your FC if you were killing algae. Dilutions introduce error into the test. The more you dilute the more the error.

Thank you Waterbear. I had read one of your posts where you indicated the false highs when the chlorine is high. Since the phenol red contained a chlorine neutralizer, I thought it was accurate. I am guessing, if the OTO test is somewhat accurate after dilution, that the chlorine is between 12 - 20 ppm. The bottle says that there is FC reading within 10 seconds, and a TC thereafter after continuous development. In your expert opinion, is that an inaccurate statement? [edit: various websites clearly state OTO only measures TC)

I'm not sure exactly what chlorine neutralizer it is, sodium something, but I wonder if the TC reading is affected by it. That's why I was wondering about the chemical formula, I believe salt is a by-product of the reaction and I did not know if that would throw the reading off.

I guess I better find some test strips that measure both FC and TC