I seem to have read somewhere that you should wait about a half hour after adding the liquid chlorine before you take a baseline measurement. That doesn't work for me at all. I suspected that I might have some algae in my pool, so it was time to give her a shock. Using the pool calculator I entered the amount that should get me to a FC of 24 (my cya is 60). Here is what I saw:
.5 hours after adding bleach: FC = 22.5
1.5 hours after adding bleach: FC = 25.5
2.5 hours after adding bleach: FC = 26.5
Yes, I had my SWG turned off (0%). No, I do not suspect operator error on performing the test. Here's what I think.
I think the number of gallons that I've been using is slightly off. I'll have to work on that one. I always add chlorine by a return and I always measure from the same spot, so maybe the pool's circulation takes a little while to fully mix the liquid chlorine.
Does anyone else see around a 2.5 - 3 hours wait in order to get accurate test results? It kinda makes doing the whole overnight loss test a time sensitive event for me. Just curious if some others have seen the same thing. FWIW, my filter was ready to be backwashed and I did so after the 2.5 hours, so perhaps the full amount of water was not circulating.