Indeed it would stop the air being pulled in You are obviously doing some research as you go - nothing wrong with that - just be careful about cutting the hole and length of the pipe that goes through the no stop into the cylinder - it could get tangled in the immersion : Yes I did that myself when an apprentice but it was on a galvanized iron hot water tank - thing is I got over it and it all worked - you are the first person I have admitted that to - it`s a weight off my mind