There are endomycos and ectomycos. Most of the reading I've done indicates that only certain kinds of trees can form symbiotic relationships with ectomycos. I doubt they can survive in an aqueous environment.
Endomycos envaginate the surface of the root and eventually colonize the root cortex. These will work in hydro, but you have to let it soak in when you inoculate it. Drench with a heavily dosed mixture several times over 2-3 hours. Apply only enough to keep the roots from drying out. When you're done, rinse well before you put the plant back into the system. In a few days, you'll see the roots plump up. Endomycos arent like soil bacteria. You don't "feed"them sugars externally.
If you just dump endomycos into your res, it won't inoculate your plants very well. Most of it will settle to the bottom.
A lot of products like great white will not only contain endomycos and ectomycos, they also contain soil bacteria, which do nothing in hydro. You can pick up a endomyco only product from a garden supply store for 1/10th the price of great white.
If you want to add bacteria to hydro, go aquaponic. It's a completely self sustaining bacteria factory: nitro bacteria to digest ammonia, other microbes that digest solid organic matter and naturally produce humic acids.
Why add pond enzymes to a sterile environment when you can just run your own pond ecosystem with aquaponics that naturally produces the bacteria that produce those enzymes? enzymes aren't living things, they're just organic catalysts produced by living things to make things happen. They're also supersensitive to heat, ph, oxidation, lockout of receptor sites.
With aquaponic, you just add fish food and you've got a disease free aqueous environment teeming with beneficials and even springtails. I have bits of leaves decomposing right on top of the roots. No problem.
Haven't changed my res or added h202 in twelve weeks now.