I have a 20 gal Long with a Fuge/Sump and need to get a skimmer. The skimmer will be in the drain portion of the sump which is approx 6" x 10". I have considered an Aqua C Urchin or the new Nano Tunze. The tank will contain mostly SPS and a clam or two so I'll need efficient skimming. Will also be using Cheato Algae for additional nutrient export. Which would you choose of the two skimmers listed or what others are out there that would fit in my available space?