You can't use these as conical fermentors by turning them upside down and installing a valve in the neck. The slope of the "shoulders" of the carboys is way too low for this. This is reportedly why the Fermentap was discontinued - it just wasn't very good for dumping the yeast.
The Fiesty(sic) Goat Brewery est. 2007 & Clusterfuggle Experimental Ales est. 2009
Primary: Saison, Berliner Weisse, sLambic I, sLambic II, IPA, 70/-
Secondary: Orange Blossom Mead, Flanders Red I
Kegged: Fat Man Porter w/ 1469, Fat Man Porter w/ 005, Centennial Falcon w/ Conan, Centennial Falcon w/ Denny's, Barrel-aged Fat Man Porter, Belgian Dark Strong, Dark Mild