Any insight on if your supplier uses filtered or non-filtered SH? In using non-filtered it decomposes more rapidly than filtered. In searching the net for anything and every thing about SH I found a company called Powell Products. They have a wealth of information and also a tool to measure the decomposition of you SH according to temp.% and days. You would need to sign up to access this feature. Really cool thing to have to help understand how long your SH will last in varing conditions. TC KIM R