Shelf life biocide fuel additive

[Shortman]

Having a sailboat I do not use a lot of fuel. I have been using the same container of Killem biocide for the three seasons I have sailed the boat. It has developed a yellow particulate that does not redissolve. It actually seemed to do that within the first year. Anyone have experience with shelf life of Killem or Biobor & how long it is safe to use?

[sailingdog]

Shortman-

Have you contacted the manufacturer? They can tell you what the shelf life of their products generally is.

[Shortman]

by email this AM

[Shortman]

Once opened and exposed to air, the shelf life of Killem is about one year. The active ingredient in this biocide is "Sodium-dithiocarbamate" which is a salt and will tend to crystalize, over a period of time, once exposed to airborne contaminants. The shelf life could last longer if kept tightly sealed and in a cool, dry environment. The product still can be used past one year, albeit it will not be as effective as fresh product.