Put the other end of the siphon hose in a bottle 1/4 full of starsan or the likes. if the hose is the wrong size for the hole with or without the grommet, you may be able to squeeze it over the inside of a three piece airlock, maybe slit the end of the hose first about .5 inches.
That will do...and it's better to put it onto the floor as you did than to set it up on top of the bucket. When it's above the wort level, enough suckback can start a siphon and pull all of that nasty blowoff water back into your brew