We may have differences in what we would all call "natural" IMO and it is only IMO simply providing a platform, light, water containing the byproducts of my feeding as in my ATS's is as natural as I can reasonably make it within the confines of my sump. I would also consider any other forum of algae Caulerpa, Cheato etc in a sump as being as natural as possible. Adding substances to encourage bacteria to grow to me is bordering on "unnatural" . I understand others have a different take on what is "natural" or "unnatural". I need to add nothing other than that stated. no reactor pellets or other foods to feed bacteria other than the byproducts of nitrification and fish waste. Another advantage is I don't have to balance between say nitrate and phosphates to feed the ATS the end product of which I simply remove that being GHA which occurs naturally both in the ocean and my ATS.
