If craving salt, then it seems to me a child would not be retaining enough, and if he ate lot’s, a lot of it could be retained at the times around the florinef dose more than it is say some 12-20 hours after the florinef dose, when all the fluid retained starts to be peed I guess.  One of the resons I spread the florinef doses out was to be more consistent with it over a 24 hour period instead of it being high at one end of the day and extremely low just before the next dose.  Kids prolly run to the loo in the last few hours before the next dose?