Copper is very effective in treating ick many marine medications use soluble copper salts or zycosin. Follow the instructions to the tee on dosage. Of course first you will need to set up a hospital tank. Crushed coral with an undergravel filter and powerhead work good for a hospital tank. As far as the question about the magnum, I would use the carbon container but fill it with an alternative medium, such as nitrex,ceramic, or bio-beads.
Carbon often removes much of the organic material needed in the marine tanks ecosystem.
By using an alternative you create more surface area for rich nitrifying bacteria to grow inside your magnum. I would only use the micron cartridge when you are trying to extract large free floating particulate matter. This Page designed By William Dean Richmond Webmaster and programmer Creative Techniques For information about advertising on Andre's Aquarium Pages.