I didn't mean to be accusatory...I just saw some things that seemed inconsistent or strange. I'm glad you're hanging in there. As for what to do about the organics or whatever the chlorine demand is coming from, the answer is it depends. If the organics are static such as a fixed amount of pollen, ammonia (which you say you don't have), lotion, etc., then it's the cumulative chlorine amount that gets rid of it. If the organics are living and reproducing such as algae, then if the chlorine level gets low and isn't maintained at or near shock level, then the chlorine demand won't go away. If you don't know what it is, then play it safe and try (as best you can) to keep the chlorine level up as much as possible.

With the TA measurement of 16, was this a pool store measurement? The standard TA test kits have one drop for every 10 ppm so you can't really get 16 ppm with your own test.

Richard