This happened to me several times until I realized that my stirring when mixing the powders was stirring in WAY too much oxygen. My efforts lasted anywhere from a week to 3 weeks, depending on how much stirring I was doing. Very frustrating! The last batch was mixed with virtually no stirring and was decanted into smaller bottles and it lasted several months with full activity.
With the recommended colder water temperatures (compared to D-76) there is the tendency to 'stir it up a bit' to get the powder to dissolve.
How much stirring were you doing while mixing? What was the water temperature? You need to adhere to the temps recommended on the package. Warm water will zap it also.
After discovering this tidbit, the last batch of D-76 was prepared without stirring; I simply poured the chemicals into a distilled water bottle at room temp, swirled the bottle several times and put it away. The next day it was completely dissolved. I am going to try this with Xtol next time around.
Last edited by Fred Aspen; 02-06-2013 at 02:11 PM. Click to view previous post history.