Study up on your corals getting nitrogen from ammonia and ammonium as not only the preferred method for some, but the only way for others. Some hosts can convert nitrate for the zoox, which are dinos, in the corals to use, but it comes at a high cost at like 30-60% more energy needed. There are not a lot of great numbers in wholesale on this other than ammonia and ammonium is way more efficient - you can find one or two on a specific clade, protein or coral, but they all caution not to use the transitive property on their results.
...so higher residual numbers for your coral are not necessary. Mine stay at .1, similar to the ocean, where you need an IC test to detect them, but I also feed a ton so my fish keep ammonia/ammonium in steady supply.
My big issue with people dosing nitrate to get nitrogen to their corals is that they usually have corals that are not thriving - hence the thought, concern and posts. Do non thriving corals need to waste energy converting backend nitrate to nitrogen instead of just using ammonia/ammonium directly. Most would be better off dosing ammonium, but they are scared of it for some reason but will put stump remover and all other kinds of unknowns into their tanks.
If you want to growth limit and/or kill/poison dinos or cyano, then higher nitrates can do this. Big thread and message board posts say that this nitrate is to allow stuff to grow to outcompete the dinos, but that is not what happens. The fauna that they talk about mostly needs to get nitrogen from food and also the dinos and cyano cannot tolerate too high of nitrate (it is deadly to all living things at some level... and different for everything).
