Just get a hose barb fitting in the correct tubing size with a NPT male thread correct to screw into the tank. Ebay is full of them- - - -no point in paying an outrageous markup at Fastenal!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!