Where the pole hose comes out of the pole I have fitted a o clip to aid the operation of the univalve as you do......just a lately I find that after an hour or so the clip slides up the pole hose and I have to force it down again.....it's as tight as it needs to be, any tighter it would be constricting the hose...any ideas?...........It's a new univalve I have fitted and this never occurred with the old one and it's the same type of pole hose.