[gimpy]

Snelly, you could probably consider the skimmer as a "mechanical" filter as it does remove a lot of the gunk in the water, just in a different way from what is generally known as a mechanical filter.

What makes you think that the supplied filter is not "enough"? You talk like every thing is looking/doing good. Don't know if I would mess with it, if that is the case. (by the way, the pic of your tank looks great to me). Not knowing what kind of system/filter you have and not being familiar with it, I can't give you any good advice concerning it. But if you don't think that it is doing its job, then go ahead and put another filter on it and see if it helps any.

If it ain't broke, don't fix it, as the old saying goes.

good luck, Frank