Your dad had a barbed fitting that fit the hose perfectly? Amazing, and congratulations!
Pond tubing drives me nuts. Every spring is a struggle. Yesterday as a matter of fact. I plugged in the pump, nothing at the far end of the kink-free tubing. Checked for voltage. Checked for plugs. Turned out the kink-free was broken underwater.
I have several barbed fittings that are either sanded down or built up with electrical tape. I hate doing things that way.
Might have to try that flexible PVC, because I keep burning thru the kink-free. I'm guessing kink-free is good for about 2 or 3 seasons. After that it gets brittle.
Threaded fittings on devices like UV filters are also a mystery to me. The threaded fittings on top of our OASE Biopress sure aren't pipe thread. I imagine they're some kind of metric??
One of these days I'm gonna rebuild as much as I can with PVC or ABS pipe and NPT. Picking up supplies is kinda on hold right now because of the virus.