Im sure this will sound like a dumb question, but...we have a 30' diameter pool. Im looking for a pole that won't get warped (or whatever is causing it) so you can't unscrew the tightening rings to lenthen or shorten the pole. I don't know how long the poles we now have will telescope out to (because they've been stuck for awhile!) but, the pole I'm looking at now will only extend to 16'. I know the halfway point in our pool would be 15'. Would having only one extra foot be enough to easily clean the center of the pool? I hate to go too much longer as the longer pole worries me that it will be too heavy when extended, but don't want to practically fall in while trying to vacuum the center where everything magically ends up!! How long should the pole I get be able to to extend? Thanks!