This may be in the wrong place, but when i wanted to start a refugium, many people pointed me in the direction of Miracle mud. It was in my fuge with chaeto and calerpa for over a year. Everything grew well with tons of micro organisms. Nitrates were still in the 40's on my 125 gallon tank. Even though i followed most suggestions to a "T" not sure i got the best deal i could have gotten. Currently im going bare bottom fuge with just chaeto growing. Stocking copepods and amphipods there. That miracle mud was a bugger to clean out of my sump!!