Is having moss in your terrarium similiar to a layer of activated charcoal?

Question

I am making a terrarium and almost everywhere (on the web) it says to add a layer of activated charcoal between the soil and drainage rocks. I plan on creating a sort of 'meadows' look by making small hills and planting it with moss then adding a few trees. Thus there will be a LOT of moss in the terrarium. Is the layer of charcoal still needed if I have so much moss? I read that moss can have some of the same effects as charcoal such as helping reduce mold and mildew but also read that it can do the exact opposite. Would this then mean that when having so much the need for a layer of activated charcoal is higher?

Some useful info

The terrarium is closed and does not have any drainage.

I will be watering it with clean pond water, so no chemicals in the water.

Answer 1

No, having a layer of moss in a closed terrarium is not similar to having activated charcoal, they serve different purposes.The activated charcoal, placed between the soil and the moss, acts as a sort of filter, absorbing smells and bacteria. There should be a half inch layer of activated charcoal spread across the surface of the growing medium, which is then covered in moss. If you want small hills, then make the hills with soil, then add the layer of charcoal,then the moss, rather than just using extra moss to give a hilly look.

Info here http://homeguides.sfgate.com/activated-charcoal-terrariums-81862.html