Recommendations for a moisture filter

I use an Airmega filter housing off Ebay & have customized the filter media inside to do a better job than the cotton filters it came with. They've done a great job for me with less volume of air to fill than the giant gold ones.
 
I use an Airmega filter housing off Ebay & have customized the filter media inside to do a better job than the cotton filters it came with. They've done a great job for me with less volume of air to fill than the giant gold ones.
description of filter above says "activated carbon" but illustration shows cotton. What did you replace the cotton with?