Firstly: Alan: Thanks for doing the D-316 testing, and for the link about storage. I hadn't seen those postings.
Originally Posted by Rafal Lukawiecki
Rafal, I have no results from long term tests yet. But I have some short term failures. For example, in one experiment, a concentration-ratio of 0.46 resulted in crystallization after a couple of weeks. I'm now testing a ratio of 0.40. The purpose of these ratio-experiments is to see how high concentration can be.
The concentrate (and sodium sulfite) will last longer if stored in the refrigerator or freezer. A few months ago, I put some concentrate in the freezer, and got no precipitation. If frozen, I would expect it to last for many years. Of course, you must remember to take the two bottles out of the freezer a few hours before you need them.