To tell if eggs have hatched remove the air and let the hatcher settle.
The egg shells will float to top and the live shrimp will go to bottom..
Use a flashlight if needed th draw the shrimp to bottom ,then syphon them out and rinse.
I use a sieve and eggs from brine shrimp direct.The SFBAY eggs were crap for me also.
I buy 1 lb and keep it in the fridge.They last over a year,hatch at 85+% and in 24 hours ..For the whole year..
I can sell small amounts of eggs if you like or you can order direct.
Artemia Hatching Sieve
This sieve fits in a Toms small Dip and Pour so you can re use the water a couple times.
Grade A Brine Shrimp Eggs
I use 2 liter bottles with cap on bottom and a rigid airline stuck in from the top to sit right in the bottom of cap.Then I remove it let eggs and shrimp settle and syphon them out with a dedicated rigid airline and tubing to the sieve.When all the shrimp and most of the water are out [fit in small dip and pour] I rinse the bottle out.You need to clean a hatcher every time you use it so this is easiest IMO
..I hatch my shrimp in 24 hours or less.
On the micro worms they can predate the fry if they are numerous enough and fry are small enough..
Most freshwater breeders like BBS because no saltwater bacteria live in fresh water easily and thus they worry less about contamination from live food.
I have used micro worms with no problem until overfed...