Quote Originally Posted by mas985 View Post
Our water district uses CC instead of FC so you might want to check that as it will throw off the measurement. According to my brother in-law who works at the regional water district, quite a few plants do this. So you might want to use distilled water instead of tap water or pre-shock the tap water and let the chlorine drop a bit before the test.
I'm not sure I understand this--if you are testing your LC/bleach for its strength, you want to test FC. I'd be shocked if CC > 0 shows up.

CC is a perfectly reasonable test of tap water to see if there's some contamination of that resulted in a CC > 0.