Is it okay to use the regs in my personal pool with just an air tank no BC? Do I need to take off the BC hose?
BC hose shouldn't leak and if it does you'll have bubble coming out, not water going in. Unless there's no air in the tank.
I doubt anyone can stop you from doing anything behind closed doors in your private pool -- but if you can drop the tank and swim up to the surface at any time I don't see why not.