Cupramine is a bit tricky as the dosage range in narrower than a chelated copper like copper power. Nonetheless, it will will work. The directions tell you to do two big doses. That can be a bit harsh on some fish. Better if you can break the dosing down into smaller doses throughout the day: AM, lunch, afternoon, PM, etc. But if it's Velvet you need to get to therapeutic level of 0.5 ppm ASAP. What kind of tester for copper do you have?Found a lfs that has the Metroplex and Cupremine but no Copper Power. Is Cupremine ok?