I have this "tank filler/drip tip" and it works to fill the tank just fine. Look at the design, it's just like the "Slap Yo momma" tool, but it's hollow so you can use it as an extra long drip tip if you like. When filling the tank, you drip the liquid down the side of the drip tip before you slide the carto up into position, don't drip into the center hole. It works exactly like the "slap yo momma".