There has beena lot of discussion on how to tell if you are buying fresh SH. Here is the sure fire way to know.
Any SH bought in 53 gal barrels, or purchased from pool supply places in 5-15 gal containers that is pumped from 53 gallon barrels, will have a sticker on the barrel showing the lot number. Look closley and you will see what you need to know.
Univar's sticker will list a 8-10 numbers, preceded by 2 letters, suck as CI72284680.
The CI stands for Cincinatta Ohio where most, if not all of Univars 12.5% SH is manufactured. The next 3 numbers are the date it was manufactured, such as July 22 in this example. Univars invoice tells you and them that the shelf date is approx.30 days. If you are buying in small quanities, ask to see the barrel it is pumped from and decide from that if you want to buy.
Hope this helps enlighten all.
Gary