Has anyone ever tried the vented silicone stoppers in place of an air lock? I saw them advertised at another supplier (Williams Brewing). The main advantage that I can see if it is, in fact, reliable would be for long term bulk aging where you would not have to be concerned about the water evaporating. They cost $4.50 for a #7 and $7.90 for a #10, so they are rather pricey. See this link: http://www.williamsbrewing.com/STOPPERS-C94.aspx