I have yet to have a DSB stop working, I like fine sand and I am still somewhat of a newb.
Mangroves are slow and steady, not the best nutrient export, but very stable.
Macros, mostly chaeto, for the win, IMO. This has worked for me. It seems very logical to me, I feed and then remove algae, it's a circle.
I look forward to reading about your NO3 reactor. I have read they work great.