Is anyone having success with the Pax Bellum N18? I bought this unit 4 or 5 months ago to run on my 120 gallon mixed reef. I'm going broke putting new chaeto in this thing. It just won't grow. I'm running it at about 180 GPH flow through. I'm adding the iron supplement and Nitrate when I need it. My NO3 is at 5 and my PO4 is at .13. I just can't keep chaeto alive in this thing. Any help would be appreciated. It's a pretty expensive piece of equipment to be used as an umbrella stand.