This is a picture of my filter. The bottom sponge cartridge I am keepig but the 2nd upper filter pad I had to replce fairly early after a month or so and replave with carbon pad which I cut to size, but I don't like the carbon much because it seems to slow the water flow coming out the head. What should I put in there instead as I don't want to get the one it came with otherwise I'll be spending too much??? ???