Thought I would give an update...
I am using LECA with an "Ebb and Flow" bucket system. My medium is being reused from the last grow, with only the root mass (as much as I could remove) cleaned from the buckets. Then the clones were dropped in and the reservoir filled with fresh water and Flora Nova Grow. I then added Canazym, hoping this would convert the old root mass to be used as food. I replace the Canazym about every week. So far, this seems to be working. I am currently about 2-3 weeks in flower and have not seen any adverse effects.