I don't know much but in my short time owning my aquarium, I have gained some Sea Hare experience. They do clean up the tank pretty nice; in fact, my cleaning crew for a while was just a fuzzy hermit and a sea hair ("Bob the Blob"). The crew worked so well together that one of my hermit's favorite snacks was those "turtle pellets :pooh:" that popped out the back of Bob :shock:. However, as many people have mentioned, the sea hare worked a little too well and he started to run out of food. Instead of just buying sea weed strips that I would have to constantly worry about feeding him, I bought this "sea grass" stuff (don't know the actual name of it) figuring that he could munch on it as he needed it, plus it added some color to my tank (no corals yet...too new) and could possibly keep growing. At first, my Tang seemed to like the stuff better than the sea hare, but after a couple of weeks, when he finally tried some for himself, Bob and the grass (not the weed...the grass) were inseparable (spell check?!?). Within another couple of weeks, algae started to come back, so i had to get some turbo snails because Bob didn't want to leave his grass, and then just a few days ago, I come home to find this shriveled up 1-inch long greenish black think laying in my sand. Still was plenty of grass left, hermit never paid him any mind, so I didn't think he was attacked...didn't know what it was. Asked the guys at my LFS and they told me that he probably ate himself to death :frustrat:
So long story short: "you're damned if you do, and you're damned if you don't". Oh, and the moral of the story: "Addiction to grass leads to death" pass it along to your friends, haha. Actually on top everything, that grass stuff really made a mess of my tank, getting stuck in my blower and filter pipes :grumble:.