So, when I flush the toilet, it starts filling the cistern like normal, but doesn't STOP when it reaches top level. Doesn't overflow but i hear water still running, (into the commode?). I have to lift (slight nudge upwards) the floating rubber ball thingy by hand (the last few millimeters) so that the filling stops. in other words, the floating rubber ball thingy doesn't fully return to the top most position when water fills in the cistern. Very annoying - any easy fix for this? I guess it's called the float ball in this pic. is the float rod part too tight? there are two screws there... One on the inlet tube where the rod connects, the other a little further ON the rod itself... shall I loosen one of them? Thanks for any help/advice.