What kind of substrate and how much LR
do you have in the tank?
Personally I would remove the carbon pad as it will assist in removing the trace elements that you want/need in your water.
When I did run a canister filter I had a layer of EHFIMECH
and a layer of EHFISUBSTRAT
I also had a white pad at the top and a blue pad between the layers. I currently am using my Eheim filter as a circulation pump.
The link below is to the different forms of eheim filter media and pads.