I have a 20 gallon tall aquarium that I am needing a new filter for. I've been looking at two filters. The Aquaclear 20 which is about $25 and has basically all good reviews. Although, some people have said that it is noisy and makes a loud sound. I am looking for a filter that is one of the quietest out there. The second filter is a Penn Plax Cascade 100 which is about $17. It has also gotten pretty good reviews but people have said that it is cheaper plastic and breaks more easily. Anyone have any ideas about which filter I should choose? Or, if there are any other great and quiet filters that aren't super pricey? Thanks!