Like @JVU says right above me, the main concern is just to make sure it's not zero. Everyone is pretty much aligned that zero is bad, even if there are wildly varying opinions in terms of what the target should be, what ratios, etc. Your result is close enough to zero that it could be zero, so I would address that regardless of whether or not that is your issue with the corals.
People tend to blame water parameters because it's all we can test for. People rarely blame something we can't test for, I guess it's human nature. Certainly there are "optimal" targets for various traces, nutrients, and so on - that likely help coral grow faster or have better color. But we're talking coral death (or slow death), which I think takes something majorly out of whack to happen. And your water parameters simply aren't majorly out of whack.
I would not take any reefing advice from anybody that has a vested interested in selling you products directly related to said advice (BRS).
