Heathd;4551653; said:
The difference between them, besides price, was the test range. The api was for med treatment level of copper whereas the salifert is for any trace of copper. Which I'm not really reading? I've tested both tanks, my tap water, my ro water too. The test color is blue, for all, but the kits color range goes from green to purple. BUT, my polysorb pad turned blue overnight and its color chart says thats copper. So, big wc tonight, test again sat.
