Makes for easier fill ups of course, but I'm getting some sort of vapor-lock or something where I have to open the top cap to get the killer feeding good again. It seems to get progressively better as the tank empties. Has anybody else noticed this? Is there another solution or is this why so many folks seem to be using top fill tanks w/this atty? If this is the solution, where can I find a decent, moderately priced (glass) top fill tank? A lot of questions I know, but I'm really trying to love my new atty - TIA!!