I've tried two of these kits: https://www.amazon.com/gp/product/B00439I1NW
It says, "Hatches Triops 5 times using a disposable hatching dish complete with thermometer, 80 Triops eggs, egg measuring spoon, nutrients, and food."
The bags the eggs come in say "eggs in sand". If that's the case, there don't seem to be that many in there. The jar doesn't seem to have anywhere near 80 eggs. Maybe 20 ~ 40 at most.
I got some eggs from Arizona Fairy Shrimp in the mail yesterday. Each pack says it contains 20 eggs, but I stopped counting at 50 and that was maybe half a pack. They really underpromised and overdelivered.
Get these instead:
They are bigger.
If you still want "sea monkeys" these are better:
http://www.arizonafairyshrimp.com/fairyshrimp.html
You can find them on ebay. I used to grow them and feed to fish lol.
Found it here
I don't know if anyone is giving them away for free but I got my kit on amazon for $8 (https://www.amazon.com/gp/product/B00439I1NW/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1). I hatched mine in a critter keeper filled with 1 Liter of spring water. I am moving them into a 7-gallon tub in a few days. I think the rule people stick to on here is 1-2 triops per gallon water.
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Edit: Link