Crazy me. I have the Taylor K2600 and after going on a trip for a week, (I had gotten the pool to shock level before I left), I came back with a dead rabbit in the pool and a CL level of 5, so I shocked again.
A couple of days later, I tested the water and could not figure our why it was taking so long for the CL level to come down. I researched and read and found where it was probably safe to swim in as long as it was below shock level. Well, the first day, I didn't check until after we went swimming. And I thought, OMG, I let my kids swim in THAT! My CL was like 19!!! (But, I justified with a CYA of 100, that below shock and not too much higher than my ideal). Our skin didn't melt so we went swimming the next two days too. The CL level went to 18 then to 17. Today, I decided to go out and drop a few hoses in the pool and start draining (until time to swim) to start lowering the CYA some more. (I've already brought it down from over 200 last fall and had decided to not fool with it anymore since I'll be moving in a June or July and I might have enough reagent to test once more or maybe twice.) Anyway, when I was out today, I tested and figured out that I had been using the 25 ml sample and counting each drop as .5, not .2! Today, I used the 10 ml sample and got a reading of 7.5 CL