Gentlemen,

Being one not to remember dates, or to write down dates, I found a solution on knowing when to check my stored water. Since I use the 6 gallon "Jerry Can" type container's, I bought some cheap, clip on Luggage Tag's.
Any piece of index card, or the back of an old business card with the month and year on it, and I know when to do my semi-annual check.

Krell