Nice to meet you metfan_ed,
I use a refugium too and I also like the concentration of animals that establish in one over time--they are a constant source of observable activity.
A skimmer simply offsets the activity of water changes in a nano, so its a luxury and not a requirement. Most of us do not run them and opt to spend the money on inhabitants or better lighting as Bingo mentioned. You'll find that many FOLR setups will house certain corals just fine as long as one stocks the fish correctly and uses at least decent lighting on the tank--many times all that is needed is a bulb switch in the current striplight setup.
There are as many ways to set up a reef as there are to customize a car, so I recommend polling several people for their techniques and you can look for consistencies among the answers, that's how I learned.
In my opinion, you can:
skip the skimmer and the power filter altogether, make sure you use a good powerhead for circulation. For the best long-term prevention against algae invasion, change about 30% of the tank water weekly, say every Sunday. It is possible to go longer but this is the best way to keep your system healthy when you are relying on dilution to buy time as oxidized fish waste builds up (you can measure this as nitrate, or NO3. For the tank you have mentioned, a range of 25-75 ppm is acceptable.)
Should you ever add on and support a refugium, this can buy water change time as we use the good macro algae in them to hold or "fix" the waste materials into plant matter as they break down and become bioavailable. One thing to consider about a refugium is that generally the plants don't fix the proteins and waste compounds directly from the water column (like a skimmer) so these items still have to be broken down by bacteria in the system. As larger proteins and compounds reduce into elemental nutrients such as nitrogen and carbon, they can become fixed into plant material (bioavailable) at that point thereby reducing the overall waste load that would otherwise become fixed by microalgae.
A skimmer removes the whole compound before it has a chance to break down, so I'd say its the most efficient form of marine filtration we have available if one was unwilling to perform rigid water changes to accomplish the same goal.
Either way, all you have to do is provide enough surface area to take the place of a filter, provide current to expose water to this surface area, and test the accumulations in the system with a few required marine test kits. From this data you set your water change schedule which is relative to your fish bioload, surface area and current. The kits you will need in the beginning are ammonia, nitrate and pH. After you have memorized your system, testing becomes less rigid because the system
will run as predicted barring any major system failures such as tank or household AC. After that, the last major risk factor is animals dead and unaccounted for. A dense reef system is much worse off here when compared to a FOWLR--> if you start out with a clown and/or a blenny and you can account for them day-to-day, don't expect your system parameters to change much. You will find a natural steady-state you can easily memorize.
Then you'll get bored and become obsessed with corals like all of us, much to the dismay of your wallet and other hobbies.
Brandon M.