Substrate is just gravel. I set the tank up with new water (primed) but I moved a hang on the back filter from another tank. For the first couple weeks before I decided to feed them an algae wafer, I think they were just filter feeding bacteria and perhaps eating off of the moss and other plants in the tank?
The tank is kept around 72F, and I do 25% water changes once a week but the nitrates never got above 5ppm. However now that I will be feeding them (maybe once ever 2-3 days), I will keep a closer eye on nitrate levels at the end of each week and post here later.
Unlike others that have grown these, my 10g is full not just 5-6" deep. This way I can use real filtration. To collect the worms, I can just vacuum them from the gravel and funnel them through a net. No messy newspapers or burlap.