After purchasing some shock for my pool, I read that it looses its potency, but if I keep in a a cool dark place it should be okay for when I use it during June-August. Now, I'm worried how long ago was it bottled? oh boy... Do these numbers printed mean anything as far as how old this might be. Thank you. (I bought early because I read there might be a shortage as people will buy to use a bleach replacement)