One more question, which I can't seem to find any information online. What are your thoughts are a growing medium that is 100% carbon (activated charcoal)? Seems like it would work nicely due to the high surface area and bacteria able to colonize more efficiently
Thanks for your time.
You sure have some interesting question there...
On vermiculite and perlite to be honest with you I never have these materials here. looks like both of these product have large surface area and light. If they don't crumble into tiny pieces then its not a problem to use.
I never tried these materials it would be difficult for me to make accurate recommendation, perlite is volcanic rock hope it do not remain floating otherwise it will be difficult in using it for growbed. This also applicable to vermiculite.
Generally only two things to consider when choosing growbed materials, 1 its must not remain floating, 2 it must not breakdown into tiny pieces then it may cause water clogging in the growbed.
On activated charcoal, we use it here for growing Orchids in pots. These are wood base charcoal and they didn't give any problem to plants. In Aquaponics since its immersed in water half of the time, it may absorb the ammonia from the fish tank. Whether this will have any effect on plant growth again I can't confirm, if you are willing to try then it would be a good knowledge for everyone doing Aquaponics.
Hope this help.