OK hopefully this is an easy one. My main return jet appears to have an outer housing that has threads, and then a 2" diameter inlet fitting that screws into it. My question is, how can I attach a hose for a fountain to this? This arrangement doesn't seem to match the standard fountain hose connectors. Would I just unscrew that inlet fitting and screw another fitting in its place? I've never attempted to unscrew it and am a bit skittish. That inlet fitting has a couple of ears inside of it, possibly to allow you to snap some sort of hose connector into it? The pool is about 15 years old.
Here's a photo: