When my lhbs closed recently I bought a secondary triple regulator and the guy gave me the wrong size tubing so ill need to get some 5/16 tubing to attach to the regulator and 5/16 duotight fittings. However i am not sure how to attach the regulator to the line coming from the primary regulator which are the 8mm OD/5mm ID lines that came with the kegerator. Is there an duotight attachment that i can get to attach (8mm/5mm on one end and 5/16 on the other) that does not have the threaded end?