I finally ditched the Maxi Jet 1200s today. I installed a Koralia 3 on each end of my tank. For those of you who use these, do you use the flow concentrator with the fish guard or not? I ask because the front of the powerhead is more open then what I have been used to and I don't want any of my fish to get nosey and stick their nose it it. While most of my fish are not strong enough to swim against 850gph, my Foxface just might be able to.