if no one knows of a good K test, how about a different question:
if you are not going to do EI, what is the "ideal" waterparameters for a fully planted tank with HC carpet and mixed high light and medium light plants?
I'm looking for a long term solution to BGA. I could drug the tank with maracyn and everything goes away, but it always comes back. I'm struggling to figure out how to find the right balance of fertilizers