What are you using for a container again? Are you keeping a decent light source on them? How long were they in the bottle after they hatched?
I use old plastic pretzel containers. They are barrel shaped. I drill two holes in the screw on lid. One for the airline and the other to let air escape.
I use IO at normal tank salinity 1.024 or so. I fill the container 3/4 with water, add the cycsts and aerate vigorously. Enough that the eggs don't settle, but not enough to blow them to the sides like a skimmer would. I keep a clip on , 60W desk lamp on the table and keep the bulb about 6 inchs from the container. Any closer and it gets too hot and you cook em.
I use the BBS in the first 24 hours. I simply unscrew the cap, let the eggs settle out, and the shrimp collect closest to the light source. I then use airline to siphon the shrimp through a brine net and rinse them. I put them right into the seahorse fry tank.
If they are over 24 hours old, I use phytofeast and fed them to make them more nutritious for the fish. IF you plan on growing them out to adulthood, you can't do it in a bottle. You'd need to set up a different tank for them.
Make sure you get a good brand egg. Some have miserable hatch rates. The decapsulated cycsts can be bought, but are expensive. If you want, you can use the recipe above or another. You can find them with a google search. Personally, I've found that only a couple/few get in with the BBS and they don't pose THAT much a problem. I'd not want them in the system in numbers.
D