Dan, I've read several times about XTOL failure, but never experienced it in 5L packages (I had one bad 1L packages but it was obvious that the content was bad: the smell, the consistence). I don't like to sit on the keg of power (a Russian expression) but I like the result, that's why I keep using XTOL.(posted 8418 days ago)OF COURSE, IT WOULD BE GREAT IF KODAK INVESTIGATES THE CAUSES OF THE FAILURE.
May be the following can be interesting: I keep the XTOL not as stock solution, but as 2x stock solution. In the first time I just had no 5L vessel on hand and decided to fit into 2.5L. That time I only occasionally used this solution and it stood more than 8 months at room temperature, in tightly closed but partially filled vessel, -- no problems! From that time I always prepare 2xStock solution for keeping. As far as I remember chemistry, the more is concentration of a substance in water, the less gases (oxygen) can be dissolved there. I also use only distilled water (my films never touch tap water).
Regards, Andrey