I have never had an XTOL failure with either 5 litre or 1 litre packages, although I did receive some 5 litre pkgs with the hard, caked powder which I returned for new. Have always mixed and dilluted with distilled water up to 1-3. have also been experimenting with adding Rodinal, as per Rodinal article at unblinkingeye.com.(posted 8076 days ago)I Use it with various Ilford and Kodak films in a JOBO. It is probably my most used developer for roll film and second to Rollo- Pyro for sheets.