Discus was looking dark again this morning, back to square one! So I did a 50% WC and treated with SERA Bactopur and a little more of the salts (SERA Ectopur) I added which apparently work well with the medicine but half dose this time as last night I did full dose and discus changed dramatically but I noticed this morning that TDS had risen to 550!! But as I say the discus seemed to love it! Check previous pics!