I have not been through this thread yet but my 2 cents.....At 64, a life-long hobbyist and in the aquatic industry-sales at the distributor level for many years-I dose bacteria in my heavily rocked, 32 year old LPS dominant 120.
I use Fauna Marin Bacto Blend, Bacto Therapy and Organic. I have also used Rebiotic, whose purpose is to "revitalize" old rock.
I also run a biopellet rector AND carbon dose every day with FM Bacto Energy. I am not in aquatic sales any more but someone referenced a thread, which I will add here.
Does this work? Is it worth the cost? I could not say 100% but I absolutely believe in a "bacteria driven system" and my simple tank does just fine, tho my PO is a constant 1.0 and NO3 usually around 45 or so.
A note on carbon dosing.....It is not just for nutrient reduction but it feeds the corals. It helps them with the uptake of PO and NO3.
https://www.reef2reef.com/threads/bacterial-driven-system-a-recipe-for-success.918102/