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I have the same high pH/TA problem, and add a similar amount of acid over the course of the first few days. You don't need to wait for a perfect pH to start using the tub, just make sure to include a stain/scale product at start up, and use more dichlor until you get the pH down, since it isn't very effective above pH 7.5. Some people use muriatic acid to offset the carbonates quicker/cheaper, so I suppose adding more dry acid at a time wouldn't hurt, BUT... If you do it, know you are increasing the risk of undiluted acid reaching the components and damaging something. Perhaps a pre-dilution would be in order. Also regardless of schedule, remember to turn all the pumps off (including a circ pump if you have it) for awhile to allow the acid to disperse, and not be drawn in in "slug". Regarding your concerns on dichlor dose, when you apply that 3-5 ppm after use, it dissipates by the time you use it the next day, so you are soaking in little or no chlorine. By doing it that way, you should maintain a clean tub, but have few concerns about suits or purple hair. It sounds as though you may be able to cut back your dose to 2 tsp and still get the 3ppm, 20 minutes after application, that you are shooting for.The Frog system and Nature 2 use silver ions (along with something else in the frog -- copper or zinc?) to help the dichlor kill more effectively and slow bacteria growth between dichlor doses. I view it as a supplement to the dichlor routine that provides me with a little cushion for inadequate or missed doses. Although you may get away with a little less dichlor (some people do use .5-1.5 ppm successfully for light usage), IMO that is not the main benefit. As WSD says: "Spare the dichlor, and spoil the hot-tub". 8-)
I have to ask why you feel Joel would need to make sure to use a stain and scale control product at startup. Would you suggest doing this at each new fill as well? Are you suggesting he use it because of his well water or do you suggest it as a general matter of course?
If you have 0.5ppm residual of free chlorine it's safe. Industry standard is 1-5ppm. As long as it's something...go for it!