It takes a while doesn't it. This is how long it took my refugium/filter to kick in as well.this natural filtration took about a year to kick in----
Nitrates at 10? How big is the refugium and how big is the main tank? Also, what fish/critters do you have in your main tank.
The reason I am asking is that my tank has undetectable nitrates.
I wonder if the miracle mud has anything to do with your nitrate levels. The organics in the mud are a source of nutrients in the system.
Fred