Copper is extremely toxic to octopuses. I recently bought a used tank and would like to keep an octopus in it. How should I go about cleaning it out? What I am planning to do: Clean the tank with a 10% bleach solution then wash with water many many times. Apply silicone on top of the previous silicone. -the posts concerning copper in this forum always seem to mention that it is absorbed by the silicone. What if I just cover up the old silicone with new silicone? I am planning on buying a new filter, skimmer, sand, and live rock. Also, the copper based medication had not been used recently on the tank. It was used 6-12 months ago and the tank ran continuously after that. What do you think? Might it work?