Betta Fry-Spirulina or Astaxanthin Powder as first foods

First, no worries I have the old stand by green water for my current betta fry. Now, I read some time ago about using both of the above as first foods for betta fry and that of other small fry egg layers. Please let me know your experience with these, any special secrets, ect..........

Thanks in advance.:help:

Update:

Both foods individually or mixed get fry started with a bang. Very good food source and large tummies on the fry. You can get a supply of both from Ken's for under $10 total.