I don't know anything about the fluval egde's filtration system but you may have to modify it to work for dwarves. I'd look at the intake first, and make sure that it wouldn't suck up dwarves or their babies - and you may have to put something over it, like a sponge. I'd also consider removing the filter media, so that brine shrimp could pass through it without clogging the filter. You could replace any sponge/fabric like material with bio-balls or ceramic media, which the brineshrimp should pass by. Or rely on rock in the tank. Live rock isn't recommended, but dead live rock would be fine.