It might be worthwhile to get one of those cheap inspection cameras that attach to a smartphone to help you inspect things a little closerThank you mp06011999. My kit did come with two O-rings per fitting which isn't obvious in the pictures. Maybe they just shrunk or something? I do know it's not very tight. It came off and went back in very easily. One thing that bothers me is that you can't really tighten the fitting by screwing it in since it won't line up with the hose the way you need. I then have to "back it up" 1/4 turn or so to line up with the hose. I'm sure that is why it has the nut to tighten things up but it still makes me nervous. It's the only fitting I have to do that with and it's the only one leaking.
I was going to write the manufacturer today if I hand't had any comments here yet so I guess I'll do that and hopefully can get some new O-rings from him. I wish I could get my head in there and inspect things a bit closer to see if there are any cracks but damn there's a lot of stuff in there.