Hatching Baby Brine Shrimp and Need Some Answers?

rock salt is about the only salt i have never used but i think you can use it as long as it does not have iodine ... there is a difference between the salts ... i have used aquarium salt, marine salt, and even table salt in a pinch ... a hydrometer is helpful it making sure you have the right salinity because when i first started hatching them, every place i looked had a different amount of salt i was supposed to add and each different kind of salt requires a different amount ... but once you have the right salinity and if the hatchery is kept warm (i kept a light from ikea over mine) they should hatch within 24 to 28 hours ... the key is the right salinity or they will not hatch and i had to learn the hard way and killed about 25 dwarf puffer fry ...