if it's right hand thread it's anti clockwise also depends at what end you look at
I'd be putting a copper or crush washer between the connector & tank too.
I was going to put a 90 deg. Street elbow , then a full bore stainless ball valve but they dont do a male and female, only Female Female , so would need a nipple and that ends up with a lot of hardware on the end.
Is the tank entry 1/2" or 3/4" ?
You can get a few pipe fittings on and it will be OK
Its 1/2” BSP . The non corroding QR is High Flow Euro
Radiospares have a full-bore 1/2" BSP valve with male/female fitting:
If you look at the thread from the thread end, not the fitting end, its wound on clockwise - or from the fitting end, hold the tape, wind the fitting clockwise.
Or use loctite 575 - you can go either direction . . .or both . . or up and down . . .
Flomasta liquid PTFE or Pipe Thread Seal. Either will work. Six quid from Screwfix.
Separate names with a comma.