Re: Is it possible to switch every year from Trichlor to Cal
You cannot use the in-line chlorinator for anything but the tabs it is designed for. You can use Cal-Hypo as a powder in the pool whenever you wish, but not in the chlorinator.
You are in my area, so you may be able to do what I do. In a normal wet winter, the CYA and CH drops, TA stays the same or goes up depending on the ratio of rainwater (TA = ~ 0?) vs tap water (TA = ~ 340).
So, in a normal spring, I test to see where the levels are for CYA and CH and start with either trichlor tabs in the chlorinator, or by adding cal-hypo powder in the shallow end and using the Wall Whale brush to mix it in. That choice depends on what level is the lowest and how long it will be until I am off on vacation. I try to run at the low end of the CYA level until that first vacation.
While I am gone on vacation, I load up the in-line chlorinator and set it at medium or low, just guessing at how much attention the pool sitter will actually pay to the chlorine levels while I am away. I hate to have them lugging bleach bottles when they have other house sitting chores to tend to. When I return, I do a full test of the pool and re-figure what source of chlorine I need to be using. Most likely I turn to bleach at that point.
However, this winter was not wet, we've had nearly no rain for 7 months, so the CYA started out at perfect levels from last years use of tabs, and the CH was perfect from last years use of cal-hypo. So, my vacation use of the in-line chlorinator this year has run the CYA up to not-good levels. (Sigh.) That will be where it sits until we get a wet Tropical Storm I guess, for I cannot drain and refill at all at this point in the drought. So for now, I use bleach, and try to keep it indoors where the heat will not degrade it too fast.