Here is my 180 Gallon set-up... I have 2 rays & about 10 peacock bass & 5 Guinacara... The tank has been running for about 4 months now with water changes every 10 days or so & levels have remained perfect. I still have not touched the Eheim as the flow is still excellent, just like the day it started. I feel this set-up has worked out well... especially considering I have a pretty big bio-load!:
The sump serves as the mechanical... is a 50 Gallon with 2 micron filter socks... each one has it's own pump for safety filtration in case 1 goes down the other is still working. The Eheim 2080 Pro is my biological and hasn't missed a beat.