You have to hydrate the cysts first.
I add the cysts to a litre of tap water and let sit for 30 minutes. This allows them to soak up enough water to make the next stage go better.
Then I add an open ended air line to keep the cysts in motion for an hour.
At the end of the hour, I add about 125ml of bleach and keep aeration going for about 4 minutes.
At the end of 4 minutes, rinse the cysts for about 3 minutes under the cold water tap to remove all traces of bleach.
This takes care of nasties that may be harbouring in the cysts.
Now take the cysts and add them to the salt water for hatching.
After hatching I siphon them off, rinse, and put in new salt water for a grow out period of a day. They CANNOT feed until they grow to the second Instar stage where they have a developed digestive tract.
Day two I siphon them out, rinse, put in new salt water and add enrichment. After 12 hours I repeat this last stage.
Rinse well again before adding nauplii to the tank.
The rinsing and water changes are to minimize any airborne bacteria from getting a toe hold on the cultures.
To enrich with phyto you need a lot of different phytos as one type doesn't have all that is needed.
I personally prefer to use powders that I blend in the blender with water for at least two minutes.
For mandarins I would think using spirulina powder, especially if you can get Algamac 3050 to add a bit to, would be great for them.
I get my spirulina powder from Brine Shrimp Direct at around $10US/pound.
The Algamac 3050 can be bought from seahorsesource.com.
You can find more information about brine shrimp at the bottom of my page,
Raising Brine Shrimp to Adult where I have some links for reading that include a DIY enrichment.