Hey everyone! I just got a big beautiful Australian harlequin tusk for my FOWLR tank. She is every bit of 7 inches if not a little larger. System has been running for two years now. I have two questions/concerns. There is still traces of copper power from when I did a in tank treatment. It is roughly reading at .21 with the Hanna checker. Will this be ok for the tusk? My other question is it normal for this species to sit around in the corners of the tank and or under rocks for periods of time throughout the day? Thank you in advance!