Do you dose phyto?I always pack as much rock as I can in my refugium. I do not grow Chaeto though, I greatly prefer Caulerpa. It grows SUPER fast, and Im able to harvest over 2 lbs weekly from my 20 gallon refugium/sump on my 75 gallon. I use it to feed the tangs, angels, and rabbitfish in my FOWLR. It prefers having some rockwork to grow on vs just floating around. Plus, I have a ton of copepods breeding in there, to constantly replenish the display and keep the mandarin and all my wrasses fat and happy.