Where is it running back out from? The spout you're pouring it into or somewhere else? Most FW tanks have a drain with a stopcock under the TT usually under the tank. There's often an overflow tube there, too. Post up where its coming from, then maybe we can help further.
2015 XLR Hyperlite 30HFS5 (mods being performed regularly)
2009 Salem LA 292fkds (gone)
Nights- ('12)23 ('13)23 ('14)15 ('15)31 ('16)25
2014 Harley Davidson FLHX (XLR cargo)
2014 VW Jetta TDI (diesel sipper, camping support vehicle)
2011 Ram 2500 CC 4X4 CTD, B&W Companion (toy hauler hauler)