if i were you, i'd ditch the bubbles altogether. you'll get a ton of salt creep cause of the bubbles popping. i'd get one of these small power heads:
http://www.marinedepot.com/md_viewIt...product=MZ3151 i had one in my 2 gallon and it worked quite nicely. i like that it's so small and you can adjust the flow. tank's lookin good!