[dr.strangelove]

If the leak appears to be coming from the very bottom of the mini-reg it could very well just be the macroline fitting. The mini-reg end cap also has an o-ring in the top of it - try greasing or replacing it if the fitting is not the source of the leak.

[beansunited1234]

I think the fitting is the source of the leak..how would I fix that? Do I have to replace it?

[dr.strangelove]

Yep, you can just swap it out.