I use fauna Marin at TSAs farm, we compared FM to ICP- analysis, Triton and oceanmo by sending multiple samples from same systems/ times and found FM to be the most consistent. Also recently learned that a few large public aquariums here in the US also utilize fauna Marin for ICP testing.
Surprised sometimes how fast I get results, I'll send out 13-14 samples at a time using 2 day shipping to coralvue - who sends them to FM in Germany and usually I get results in 7-8 business days or less