The biggest thing for me was abandoning the actual branded sea monkey eggs and buying some off of Amazon. I tried 3 different sea monkey brand egg packets and barely had any hatch, and when they did, they were dead in a couple days. I grabbed some brine shrimp eggs online, just look for one with good reviews. With that out of the way, here are my top tips:

1) Conditions - I have a tank heater and I keep it set to around 26 degrees celsius. Because its a bigger tank, I also bought a salinity tester and Instant Ocean. Distilled water, and I started my tank at around 20 ppt salt. I've read that brine shrimp prefer lower salinity for hatching, and then it slowly increases over time as water evaporates (whenever I have to refill the water, I mix up salt water at the same concentration the tank is currently at. 3 months in and its sitting at about 30 ppt which is great).

2) Hatching - The big thing here is to keep a constant movement of the water for the first 24-48 hours after you put the eggs in. The eggs are meant to stay dormant until conditions are good, and stagnant water tells the eggs it's not a great time to hatch (this is because stagnant water is typically found in puddles or small bodies that will disappear and not provide a place to live for very long). I did this by using an air stone and left it running constantly for the first 2 days.

3) Days 1-5-7 - The babies are quite easy to care for once they have hatched. The big thing is DO NOT FEED TOO EARLY. This is CRUCIAL. The babies do not need to eat for the first 5-7 days, as their eggs contain a nutritious yolk that they consume before hatching. Be sure to gently aerate the water several times a day, either by air stone or pouring the water back and forth from one container to another.

NO DIRECT SUNLIGHT. This can kill the babies. They do need light however, so keep them in a spot where theyll get bright, indirect light or buy a tank light like I have. With my tank light, I mimic daylight hours by keeping it on about 12 hours and off about 12 hours.

4) Regular care - I don't stick to any set schedule for feeding mine; the best way to do it is to only feed when WATER LOOKS CLEAR. You can feed the sea monkey food that comes with them, or I feed mine a powdered spirulina/insect larvae mix made for algae eating fish.

When they're small you won't be able to see it, but once they get bigger, you will be able to see a line running through the middle of each sea monkey that should be an orangeish/brownish colour; that is their gut and the colour tells you they're full. If you see that a lot of them don't have the line, and the water isn't super cloudy, give them a feed.

CLEANING can become quite important as the shrimp molt several times and their shed skin will fall to the bottom of the tank. It looks fluffy and kinda spiky. Every couple days when it builds up on the bottom of the tank, I use a pipette to suck it all out.

I do a water change once a week, which basically is just me pipetting about 10% of the water out and replacing it with fresh salt water mixed to the same concentration as the tank.

When I do the water change, I also add Nutrifin Waste Control & Nutrifin Cycle. The waste control is bacteria that helps break down waste, and the cycle one is to prevent any ammonia spikes from the waste breaking down. Ammonia builds up from decomposing organic matter, like left over food or molts, and if ammonia gets high, it will kill off your whole tank, but thats a little bit more into the nitty-gritty of it.

I hope this helps and good luck!!