My torts are on wind down ready for hibernating in a few weeks, with them not eating I wondered if they still needed the supplements? If so, how do they get them?
How old is your tort? How long have you had your tort? If you have stopped offering food then I would not be concerned about trying to offer supplements, after all---if you have been preparing them for the entire year from last brumation to this upcoming one...then they should have obtained what they need and well hydrated....if you are unsure of their over all condition then I would also be unsure of brumating them...
No need for calcium now, it is demanded for the growing season. I don't know if is not even dangerous by reducing the gut pH, since it will not be entirely used, and neither the excess fully excreted, both due to slower metabolism. Just plain water for now, they only need system cleanup.