Nikki, actually I had the same situation. There was never any bryopsis in my reef but there was some hair and other types of algae. Lettuce slugs will live on other types of algae but they will not really thrive or reproduce more than once. They really do not eat anything, they just suck out the chloroplasts. If you give them bryopsis they turn it into a slimy mush. They may take a little nutrition from hair algae but as I said I have studied them extensively and I supplied a research organization with them but the amount of hair algae they may "eat" is so small as to be negliable. I know they sell them for that reason but you would be wasting your money if your goal is algae control. Even with about 125 of them in my reef I had some hair algae. I even watched them under a magnifying glass for hours to see if they would eat it but no luck. I really wished they did, I would be a zillionaire by now.
Paul
:badgrin:
Paul
:badgrin: