I would agree about the clam and it has long since been moved to another tank, but the sps and fish did just fine. I will also mention that I did frequent water changes and "overskimmed" by using a skimmer meant for a tank about 20 times bigger than the 5.5.
The key to nanos is that you must keep on top of the maintenance. Daily attention, if not more often is required. While they seem like they would be less work than a bigger tank, the opposite is true.