Although I just started an Aquaclear 30 on a 20 gallon high I already love it. MUCH quieter than the bio-wheel on my 10 gallon tank. I run it with 2 sponges in the basket. I say go for it! They are a VERY popular filter.
for a 225 youll need 4 AC300's at a minimum unless you do some custom work to make the filter better. I have 3 running on a 55 gallon and it just cuts it. For my 90 I plan on a XP3 with 2 AC500's
I'f you're referring to the Proclear Aqua Clear wet/dry filters, then I would feel comfortable with a 300 model on a 225 gallon tank with a moderate fish load. I had originally wanted to put one on my 210g, but the design of the stand did not allow me to.
To the two posters above me, check out this site: http://www.proclearaquatics.com/
Those are the filters that the original poster was inquiring about.