Years ago I bought a filter cage that was covered in fabric to replace my cartridge filters. I need to replace the fabric covers and the place I bought it at no longer exists. So I am going to make my own. But I am not sure what type of fabric to order. I have felt and PTFE MEMBRANE SURFACE FELT and I am sure there are others available but I am not sure which one is right and safe. I would definitely be interested in other types of fabric if you wanted to make suggestions. Also what microns size do I want?