I can only tell you what happened in my ULNS. I have tried everything to raise nitrate and it just doesn’t go up. When I started dosing nitrate, I had massive algae blooms and some of the SPS did not like it and started receding. I quit dosing and everything came back to normal.
I have run 0 nitrates and 0 phosphates for over 8 months and the Corals were healthy and growing fast (until my lighting mistake). I personally wouldn’t push to get them up.
I do alternate mass quantities of reef chili and reef roids every day. I still don’t get a PHos or NO3 reading, but you can visibly see that some Corals are healthier looking.
Really, it’s a cursed blessing. I’d rather be on the ultra low end than not being able to get them down. IMHO