IMHO API liquid+tube test kits are completely useless and inaccurate in saltwater. Whenever you buy the "saltwater" variety I am 100% certain it is the exact same chemicals as the freshwater version. Nitrates and phosphate never changes color from the original color of the reagent solution when first mixed, etc. I am not a marine ecologist but I know for a fact there is at least some nitrate and phosphate present in my tank on a regular basis due to feeding. Whenever there is a loss I test for ammonia and it doesn't change color. It only changed colors when I first cycled and intentionally dosed ammonia. I've used this kit for 7+ years in my planted tank and I always get rational results. Thoughts?