For a tank that size, you probably don't have a whole lot of room.
For a power filter, maybe a whisper or the smaller emporer. I could be wrong, but a Prizm skimmer might be about the smallest that does a good job once you figure out how to use it. I use a Prizm on my 55 and also have the larger Emporer 400. I am very pleased with both.
Just my own oppinion.