RO water will tie up some nutrients to harden itself up a bit, Cal/Mag being of some of the more susceptible. If your living soil is balanced properly you shouldn't have an issue using RO water with a living soil. It's a little different as you are looking to provide the microbial life what it needs to break things down for your plants. You're not dealing with soluble nutrients in the same way as you are out of the bottle. With living soil you feed your soil, not your plants.

I am still learning a lot as far as organic growing, there may be variables I am unaware of related to this issue.

Thanks for the comment!