I have previously been using liquid chlorine with stable and predictable results with minimal "shocking" ever needed. In anticipation of leaving town for 2 weeks in a couple of months, and having a neighbor to keep an eye on things, I bought a bucket of Trichlor tabs at Costco. Container describes them as being blue, but these are definitely white so maybe they are old and the color faded out? The chlorine output from a total of 12 tabs at 6 per week has been minimal. I have continued using my usual 32oz of liquid chlorine except for two of the days as an experiment. My combined chlorine has usually been zero but occasionally has gone to .5. Yesterday it went up to 1.0 I then added HTH Calcium Hypochlorite 53% granular chlorine and next day my FC only increased from 2.5 to 3.5 even with tabs in the floater. I also am left with a white powdered residual oh the pool floor which I will have to vacuum out (calcium carbonate, maybe?).
I am glad I tested these things out at least two months before I intended leaving. I am now thinking of just asking my neighbor to add 32 oz of Chlorine daily and buying him extra beer along with returning those blue but washed out Clorex tabs to Costco. Am I missing something?