Join Date: Mar 2004
Location: S.F. Bay Area, CA, USA
I've tried a panty hose, but it *completely* blocked the flow of water. Then I tried tulle (that netting stuff used for bridal veils and under wedding dresses). I had some tulle circles left over from when I made favors for my baby-welcoming party almost five years ago. I think I got packs from a party store or Michael's crafts store. I'm not sure if the holes are small enough to keep out newborn shrimp, but they might sell them in a smaller weave size, or you could do 2-3 layers.
How big is this nano tank, BTW? If it's 5.5 gallons or smaller, you might want to consider a palm filter - either AZOO or Red Sea. It's a lot easier to control the flow on those things.