Nitrate Test Kit - Red Sea Pro vs Salifert

[Myka]

I've been liking the Red Sea NO3 kit. When I do my testing, I always do it first, so while I'm waiting for it to develop I do the rest of the tests. The readings seem to match what I am figuring out mathematically for my NaNO3 dosing. The Salifert kit always reads about half what the Red Sea kit tests. I'm only reading <1 ppm though, I haven't tried it for more yet.