when I ran my pool I used the filter that came with it to keep the water moving and nothing more, it was worthless for anything else. You can look up my pool thread on this site. I used a fx5 and a HUGE Brute trash can stuffed full of media as my filtration. Did you disclose to the person paying the bills that they can expect at least a 50 dollar jump in power monthly?
edit:
I just read this that you posted while i was typing:
so what kind of filteration system am i looking at getting/building?
I think that you need to do a lot more research on your own and then ask questions about what you saw that you didnt understand instead of doing nothing but dreaming off all these huge tanks. There are tons of threads on here that you can read and learn from. Most of which will require you to tailor them to your own needs.