I'm trying the elevated magnesium method to control a Bryopsis infestation. I'd like to get a magnesium test kit that will handle high ranges (like up to 1800 ppm). The Salifert test says it is good up to 1500 ppm, but I need to go higher. Does anyone have a recommendation for a test (maybe Seachem or Red Sea?) that will measure the high Mg range? Anyone have experience with multiple kits that could compare them on how easy they were to use and how accurate they seem?