If they are loose what you can do is to take some flat dental floss and wrap around the drip tip a spin or two and then put the o-ring back on (yeah, remove the o-ring first) then wrap in the indent a time or how ever is necessary for your tank, then put the o-ring back on and give it a go.
The drip tip that came with my Protank 2 was terribly loose and this worked for me.