The low range testers units are integers. The normal one measures in decimals, so this was not a low range tester test (or the guy did the ppm conversion and that's the number being reported). 0.04 is the high end of perfect, so it's great, but keep an eye out. I keep telling people this as a precaution. Hannah phodphate tests work best when you follow the directions precisely. When they say mix for two minutes, they mean the full 120 seconds.