Ohh my i just changed my Fx3 and i mean whatta workout. hahah But i love that thing it does wonders! On my 55 it is just phenominal, i mean i originally had a top fin 55g filter that came with the tank and it was s**t! I had to change the filter media like every two weeks it wouldnt even last a month. Well then i was looking for a new filter and i came across this little beautie! Well if any of you were looking for a good filter then i suggest a Fluval it is wonderful!