We are looking to up our CUC gang and have a quick question. What is the most useful for a bare bottom tank, a Serpent Starfish or a Cleaner Shrimp? We've got a Waterbox 70.3 that has been up roughly 5 months. We have a red Tuxedo Urchin, 4 Trochus Snails, and two dwarf hermit crabs as our current crew. We also have 8 saltwater acclimated mollies to cycle the bacterial load. We are ready to order our first true saltwater fish and get one or the other as an additional CUC. Any thoughts, recommendations, or concerns with one or the other?