[Chasmodes]

Well, I like the crab more than the Ulva, so, I guess I'll view the Ulva as temporary beauty but also as food. In the wild, it's a sign of high nutrient waters, so probably not an indicator of a healthy environment (as you stated) in the wild or in my tank. Eel grass, however, would be a different story. I would either keep the crab in the oyster reef tank and move the eel grass and make a lagoon tank (for seahorses, sticklebacks, rainwater killies, gobies, etc.) or move the crab. Not sure yet. I guess it would depend on how the grasses are doing soon after collection (I got a good tip on where to get it next summer). Also, this would be in my 100g tank. I obtained a 40g tank which might serve as a good Chesapeake Bay sea grass tank. You have options when it comes to having more than one tank, you can create 2 versions of the same biotope! I think with better lighting, the Ulva growth would outpace predation. My light is a cheap one.