It would be fine to use but only AFTER you leech out EVERY BIT of ammonia, otherwise you'll burn your frogs. Amphibians are extremely sensitive.
You could also set it up, plant it, and let the plants suck up all the ammonia before you add frogs. You'll know when it's safe by testing the water that falls through the false bottom for ammonia, nitrite and nitrate. Let the bacteria fully colonize the aquasoil and convert all ammonia to nitrate, then flush the media with enough water until the nitrate is as a safe low level.