Sorry to hear about the loss of the cardinals and clowns - and your aquascape!. Velvet is a bear.
You've been getting excellent advice in this thread so far - my thanks to @Smo, @Big G and @4FordFamily, as my notifications for the thread dropped somehow.
You can switch to Coppersafe, but should do that water change, so you know what you've got in the tank. With a mismatched test kit and some level of "the other copper" in the tank, your readings may be inaccurate - and some of these tests are hard enough to read as it stands!
Copper treatment only lasts 14 days if you're going to move the fish to a second, clean & uncontaminated QT immediately after treatment. If you're going to keep them in the same 20-gallon, then treatment should last 30 days.
~Bruce
You've been getting excellent advice in this thread so far - my thanks to @Smo, @Big G and @4FordFamily, as my notifications for the thread dropped somehow.
You can switch to Coppersafe, but should do that water change, so you know what you've got in the tank. With a mismatched test kit and some level of "the other copper" in the tank, your readings may be inaccurate - and some of these tests are hard enough to read as it stands!
Copper treatment only lasts 14 days if you're going to move the fish to a second, clean & uncontaminated QT immediately after treatment. If you're going to keep them in the same 20-gallon, then treatment should last 30 days.
~Bruce