Alright, my girlfriend has a 15 gallon column as her very first fish tank thanks to me lol. We bought it brand new about 3 months ago and it came with I believe an aqueon whisper 20 or something like that. It's just not powerful enough for me. I want something with a longer intake tube, good biological filtration, but not too much of a flow coming out since not much surface area. I like ac 30's or 50's but there intakes are short aren't they? Thanks!