Tonight when you run your tests, run all of them including the CC test and post the results here. That CC is the tell tale to the impact of organics, you want that < .5 on your test. It will vary some from time to time, but you don't want 1, you would want to SLAM to kill whatever is going on. Make sense? Again, you will get a feel for it.
It's funny, as you start testing, you do start to understand why a certain test may have come back a certain way and know IF you need to address it or not. Could be you tested too soon for something or you may decide to wait another day to test it to see if you are right.
Back with running to the pool store, #1, you didn't go every day or every other day most likely to have your water tested, so by the time something was out of order + assuming they caught it + assuming they gave you good advice to adjust it, it was probably really out of order, #2 because you are testing onsite you are going to catch things much faster which will result in smaller adjustments and avoid getting anything overblown. So waiting a day to "confirm" is not equal to waiting a week until you plan to hit the store again.
All these little nuances is what really extrapolated the power of TFP in my personal experiences.