Originally Posted by EricR
I am really glad that you posted this information. When I originally introduced the Pyrocat-HD formula I was very conservative in the estimated stability of the stock solutions because at the time I had only about six months of experience in working with the final formula. So I gave an estimated shell life of 1/2 of that time, i.e. three months, to be on the safe side. And the original formula was for only 100ml of Stock A and B solutions, as some might recall, in the e anticipation that most users would need to mix again in three months or less.
Now that several years have passed, and I have had a lot of experience with the keeping qualities of the stock solutions, I know for a fact that the shell life in partially full bottles (assuming mixing with distilled water) is at least two years, and perhaps even more. But I have been reluctant to state this fact without verification from actual work in the field by others. So for the reality check I thank you.