I have a 75 gal tank with a marineland tidepool filter. It has some cermic biorings, carbon, and a filter pad. I also have a sea clone protien skimmer. The problem is that i could not get a cb bimac for a few months so i got a really nice lionfish, then i got a tessalated eel, saddlebutterfly fish, and a harliquin tusk fish. Well the butterfly brought ick in and i did not want to lose $400 in fish so i added a bunch of rid-ich. Almost a whole large bottle. Well most of the fish ended up diying from the ich or the medicine. The eel jumped out. So now i have an empty tank again, but can i still get an octo? I am thinking not because there is still a blue tint at the seals and some of the plastic so i think the medicine is still in there and it might kill the octo because they are so sensitive. Let me know what you think. Thanks for your time, Jake.