We've been using two small 25sq ft cartridges. Upgrading to 100 sq ft cartridges on the new system. There is an incredible reef system on Reef Central that has a Pentair Rainbow RTL 100 or something very similar for mechanical filtration. There's an MFK member from Mexico City with a large tank with what appears to be an RTL type filter Unfortunately, I'm at the lake for a few days, so can't post pics of other setups with closed loop mechanical filtration utilizing RTL type filters.
sent from my DROID RAZR MAXX
Ever thought about using these for your new system?

