I use the Blue plastic jugs too. I made an adapter to a Vinyl hose out of an old cap. I was using the big 6 gallon jobs, but now I use 4 of the 3 gallon square ones. They fit better on the folding hand cart I use and are less painful to lift.
Put the hose in the gravity fill port and up end the jug.
The small hole in the cap only goes through the white plastic and not the inner seal foam. That way it will "bubble" all around the foam and not leak so much.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW