The more disciplined you can be with mechanical removal (which a skimmer does as well as conventional floss in a filter) the lower the rate of nutrient injection into the system (and thus lower rates of Nitrate creation). I have the Tunze 9004 on my 14 gallon cube, and it is very easy to clean and maintain and does a reasonable job. There are definitely in-sump skimmers which are more efficient, but for a smallish tank the ease with which you can clean this one is a definite plus. Some great husbandry advice I was given years ago is that you clean socks (or other floss material if possible) and skimmer daily. The rational is that the more physical matter you can pull from contact with the water column, the less breakdown into nitrate (slower rate of production). Even though some will argue that the skimmer pulls the skimmate out of the water column, you quickly can observe that there is a LOT of gunk collected in the neck of the cup which remains in contact with the water and is also thus a good candidate for frequent cleaning/removal.
As to the Comline filter, you will have to decide if that is easy enough for you to clean frequently and store the media you want to deliver. The fact that it promotes a bit of surface filtering is definitely a plus, but the skimmer does this as well. (Aim to have the water level at least half way up the slits on the skimmer or higher). I switched the Comline filter for the skimmer in my 14 gallon cube, but that was more due to space than anything. In its place I put an Aquaclear 70 back filter, and yes, I change the sponge on the inlet as close to daily as possible. (This is really easy to do, as I don't even unplug the filter, just pull the pipe up and out, rinse the sponge thoroughly, taking about two minutes, then back in with the power still on and the waterline still at the top of the box).
The other good piece of husbandry advice is that you keep your sand bed and rock work clean with at least weekly (preferably right before a water change) stirring of the sand bed (to release the gunk into the water to be trapped in filter and skimmer) as well as blasting of the rock either with a powerhead (controlling flow with your palm against the inlet) or a turkey baster if you are more masochistic and like a workout. The sand bed can be done in portions if there are concerns of stirring up too much bacteria, but frankly I did the entire bed over several days and never had a problem. If you leave the bed for a few weeks and then stir it you will definitely notice the difference that daily/weekly stirring has!
Hope this helps. Happy reefing! :)
