I'm a tech a a wastewater plant, but not an RV'er so things may be different in that world. Two weeks is no where near long enough for the anaerobic digestion process to take its course no matter what product you add. Solids will break down naturally and the waste will go septic in a matter of...
I work for a waste water treatment plant. We've got a couple of them floating around to take the huge manhole covers off with. Works pretty good and is way easier than trying to pry them off with a hook.