I have both running on my 150. I like them both but the price of the CF500 is much easier on the wallet than the FX5. THe CF500 is 525gal/hr and the FX5 is 925gal/hr. For a little more than the cost of one FX5 you could get 2x CF500 and have a higher turnover rate. I like my FX5 but I really like my CF500s too Either way they are both great filters!