More Cu
I can still smell just a little bit of H2S.
So this is hopefully the last 0.1 ppm of Cu. The total added is 0.3 ppm, way under the legal limit for added Cu, and also under the limit for residual Cu. Actually, probably no more than 0.1 ppm residual is left, since I can still smell the H2S. The rest of the Cu has bound to the H2S and precipitated out.