Outdoor filter should not use carbon media.
Why? Because outdoor filter is meant to filter off bigger sediments only like dirt. After outdoor filter the water source will go to your house water tank, which the water will stay there for a very long period of time. Carbon media effectively remove chlorine which use to kill bacteria & germs but your it's no longer in your water and 2nd contamination can happen in our house water tank. Many outdoor filter doesn't use carbon because of this. You rarely find outdoor filter with carbon.