It would be a bigger skimmer for sure to handle a 55 gallon tank, but if you're doing it...I suggest a little bit of a modification to it. I don't know how you feel about bio balls, and bio media, but I personally hate the nitrate factory side of them.

On my seahorse tank, I removed the bio stuff in the bakpak and replaced it with chaeto and caulpra. THey sell nice little bright LED lights you can put on the side of it and create a nice little natural filter out of it. The skimming side of it works the same. I have rots, copepods, and all sorts of stuff growing in there...really helps out.