Hello; I am not sure of this and do not have personal experience. In a thread a few weeks back we (some of the forum members) were trying to diagnose why a member was losing fish and having water issues after a water change.I would put that to evaporation? meaning the dosage is no longer exact. safe or prime is a salt, hydrosulfitie salt. I may be wrong but think a twinky shelf life has nothing on safe or prime.
If I recall the member was getting his water treatment chemicals from a local fish shop. The fish shop was mixing up the chemical and putting it in their own bottles. Some one posted that the liquid form has a limited shelf life of about a year. I may be guilty of propogating bad information. I use the term "reported" with things like this when I do not have the personal experience to rely on.
Pops, your post makes sense. Thanks for the constructive criticism. Perhaps the shelf life question can be addressed by others.