I use this frequently on reef and planted tanks without ill effects. I even use it with super glue gel. Just be warned that once it dries it is like concrete so don't plan on moving it!
I'm trying to connect a PVC pipe to my filter output pipe.Safe for drinking water is safe for the aquarium. Also, just my opinion, but any time you see something used in the salt water hobby, it is more than good enough for freshwater. I think you should be good.
What do you need JBweld for on a spray bar though?