I wasn't paying attention in science class when they talked about ionic solutions and diffusion of areas of higher concentration to areas of lower concentration.
So I can't accuratly give you a time, but let the shrimp collect for 30 mins, then feed. And then repeat with more water from the fry tank if you need more shrimp.
The method I use is good IMO because once they hatch in my incubator, I move them over to the seperator where they can live for 2 more days. I then hatch a new batch if I need while they are living still, so I have a constant food supply.
I think the net would be better for larger adult brine shrimp, but I can never raise alot to be large. Also they have alot more protein at the just hatched stage so it wouldn't make sense to raise them to adult size, unless you wanted to breed them or feed them to larger fish who can't see small baby brines.
For my next hatch, I used the eggs I got off eBay with my own mix.
1-1/2 tablespoons of Aquarium Salt.
1/2 tablespoon of Epson Salt.
Pinch of Baking Soda.
1/2 teaspoon of eggs.
I'm going to see how the results are.
Also note, that the incubator I use (upside down soda bottle) has a curved rounded bottom which keeps the eggs tumbling and constantly moving. If the eggs, settle they will hatch alot slower or not at all.