Quote Originally Posted by jaded
I have the same question... I hold 35 or 40 gallons for top off. Lately I've noticed a slick feeling on the side of the storage container.

???
Yep, same here. The other day I let it get pretty low and stirred it up a bunch and some of the slimy stuff came off into the water, just some simple greenish algae stuff. I figured it was probably harmless but since I had some time I emptied it completely and wiped the can totally dry/clean with towels and then started filling it back up.