No problemo Mike.
Cracked or Broken cell Chlorella just makes it easier to digest for us humans. How they measure digestibility is beyond me. Like you said, probably snake oil.
However, for an animal that eats algae, like shrimps, I doubt they will have any issues. A shrimp will have a digestive system that will be able to handle algae since this is part of their normal diet. So choose which ever is cheaper or more readily available. If price isn't a factor, then go with the cracked cell variety. At least you could eat it too. I have so much chlorella, that I have recently started adding it to my smoothies !!
Garlic isn't necessary in this recipe. You can add it for it's nutritional value, but it's not needed for an attractant.
The shrimps will swarm onto this food without garlic. Chlorella and Spirulina have a very strong odour by themselves. Those smells will provide a more natural attractant than garlic. Save your garlic for other uses.
High heats are not good for Chlorella, destroys it's nutritional value. So do NOT add them while the agar is still on the stove.
You can add the other ingredients in while it is still on the stove. But let the agar cool as much as you can before combining the Chlorella. This is the tricky part. When to add Chlorella to the agar BEFORE it solidifies.
I let my agar mix cool for 10 minutes, stirring constantly so it doesn't set, then add Chlorella and stir vigorously again to mix that powder in. The pro might have been right about adding ingredients while the agar is hot, but they weren't cooking agar with Chlorella.
Nice tip about presoaking the agar. I didn't have any issues with it gelling up, but will try it next batch anyway.
My shrimps are looking super healthy after 3 weeks on this food.
Where are you getting your Astaxanthin powder from?
I need to source some.