So I got a bunch of free tanks that I want to turn into reef tanks but the silicon is blue does that mean the tank has been dieses with some sort of medication that has cooper in it and if so will it kill my corals?
+1 Erin. Medications that contain malachite green can stain the silicone. If someone has used those meds in the tank, I can almost guarantee that they've also used copper based meds at some point.