I have read numerous times substrate don't matter, but yet I have read things like egg shells or crushed coral or other calcium type substrates. (I have read Mustafa uses sand, but that could even have a mineral content)
With that said (& yes I'm notorious for reading into things & it can get me in trouble by assuming things that are not true

) do these shrimp need some sort of calcium substance for there exo-skeleton (or whatever that's called) I am setting up a little .5 gallon tank for my nephew with a couple of shrimp, some of Mustafa's chaeto, & a small 6500K led light. Do I need a mineral (crushed coral, eggshell or whatever) stone in the tank ? Or is bare bottom & a small hunk of cheato all I need ?
Thanks,
Dan
Edit: I guess another question I have is do you need to add iodine to the tank ? I remember doing that in my reef tank, if I remember correctly it was for the shrimp ? What about a calcium additive for a reef tank ? (kalkwater or something like that, it's been 10 years since I had my reef tank)