I have leaf litter in my indoor jars, ready to go. Ostracods have already appeared there. I just haven’t been able to expand the moina after hatching. They live around a week, but haven’t taken off fast enough to transfer them to the larger container. I think partly I might be killing them when adding chlorella/fish mix.
Have you tested the Chlorella culture for ammonia?
Also what water are you keeping the Moina in? Mine always similarly died if I kept them in the RO water (with a dash of potassium carbonate to ensure a positive pH) that I hatched them in - but my main growing on tank was tap water based, so plenty of calcium, which I suspect they need in order to grow their carapace.