I found a bag of microplex that I had ordered a year or so ago and would like to use this up, I have been using TMG since then. What amount should I add to 500ml of water to make the same dose as TMG? The analysis of microplex is: Mg-5.4% Bo-0.5% Co-0.05% Cu-1.5% Fe-4.0% Mn-4.0% Mb-0.1% Zn-1.5% Is the copper going to be too high for discus? Matt