I have some fish in a QT tank and I’ve been using copper power for the tank. All that is in the tank is a few pvc pieces for hides for the fish and a foam block for the filter. The copper levels keep dropping overnight. Last night the level was at 2 ppm and this morning it was at 1.09. I’m using the Hana high range checker. I didn’t think I’d have to keep redosing with nothing to absorb the copper. I can’t imagine the foam block is absorbing copper. I suppose it’s possible the pvc is but I wouldn’t think so. Also if I dose like .5ml of copper and then test it shows the levels back up closer to 2 again. Seems like a small amount to raise that much. Fish all seem ok and no signs of the velvet I’m dealing with just need to know if anyone has similar experience or thoughts.