Interesting recipe. I am big into DIY foods because I feel it truly helps me control what is going into my fish food. Now was the choice of agar just because it stays gelled at room temp better, or were there any other reasons?
It was mostly because of the gel temperature, but also because it is plant-derived and it seemed to me that it would be more digestible for herbivorous fish, like otos (but that's just sort of a gut feeling, not based on any scientific evidence).
I know we use it at school for growing colonies so i was shocked to hear about using as a gelatin substitute.
Yep, most of us think "petri dish" when we hear "agar" (which is why it has to be refrigerated and used quickly once it has been prepared into gel!) but it has been used for people food for a long time.
Did you figure out the concentrations of powders by trial and error?
Nope, I just followed the directions on the container.
: It's pretty tolerant though. Less agar makes a softer gel, more agar makes a stiffer gel. There isn't a "magic" amount.
Do you have a base amount of agar to amount of powders?
Yes, both mixes are 1 part agar to 12 parts other stuff (by volume).
I ask because I wish to use Astaxanthinin this recipe as a way to increase the color of my red cherry shrimp ^_^.
The mix makes a pretty firm gel at 1 part mix to 4 parts water. You should be able to add quite a bit of other ingredients without a problem---that was one of the main reasons for making the mix in the first place. You'll just have to use trial and error to figure out the right amounts, but if you make a batch that doesn't work, you can melt it and add more stuff and let it reset until you are happy with it. If you find you need a mix with more agar to accommodate the volume of other ingredients you want, let me know and we'll work something out.
Any info you could tell me well be greatley appreciated!
Hope that helps!