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So it's just basil and dill? Basil is on the safe list. Dill is on the unsafe though I'm not clear on why - most things there are guesses based on what the crabs ignore and/or things that are toxic to other animals (though not always the crabs).
I was thinking it was just a seed mix. I'm not sure about the clay. Maybe sprout them outside of the tank first? Assuming whatever the clay stuff is is safe.