Maybe. I had a large... I mean LARGE skimmer on my 45g once... I think it was rated for 180g... the problem that I experienced was that it didn't skim very well because the neck of the skimmer always got crudded up first. I read about this being an issue on oversized skimmers. However, a "rated" 300g or 350g skimmer on a 225g system isn't too bad at all. In fact, it may actually match up. Most skimmers are fairly overrated.
Brandon