I've been testing between both Salifert and Elos and so far I've been liking the Salifert kits better. The Mg was the last kit I tested between both these brands and the Salifert seems easier and more more reliable. When testing with Salifert I would always get around 1400's and with the Elos it would vary from 1400 to 1200 testing it the same way every time. Maybe it was just my kit perhaps, but I'm not into the Elos Mg kit anymore.