I use carto tanks exclusivly. I will often fill a tank with a juice I seldom vape and Ill vape it for a few hours. Then it goes in a drawer for a month or three. When im ready for something sweet ill pull it out and vape it. Then I got to thinking. If that carto and tank was full of water it would probably get moldy after sitting there for two months, wet and dark. Why would pg or vg be any different? Is this something I should be concerned about?