What kind of liverock is it (e.g. Fiji) and what volume (approximately) does it take up? Â½ the tank? A third? ... From what you've said already though. I'd get a few more lbs. LR
(about 15 to 25, I think) and ditch the Fluval. If it has foam in it, it's just trapping particles and creating nitrate. That's what I think, I'd definitely get more opinions though. Hope this helps ya.
125 gallon saltwater: 55gal sump, 4 Blue-Green Chromis, Purple Tang, True Perc, Firefish, Royal Gramma, 5 Ricordea, Bubble Coral, 15 Pulsing Xenia, Green Star Polyps, Deresa clam, Green-Tip Torch Coral (about 11 "heads"!), Orange Montipora Cap, Purple M. Digitata, Green Slimer Acro. Yongei, 3 Orange M. Digitata, Pink&Green Acro. Millepora