HELP! New black moor with ick?

I bought two fish today, a black moor and a telescope eye calico. The black moor looks like he has ick so I put in a tetra ick guard tablet and took out (what I think) is the carbon filter from my tank. The only thing left in the filter now is a little black thing that basically looks like a piece of sponge. How long can I leave the carbon out without killing my new goldfish? Any advice?