Hi, i'm still trying to figure out how to keep the sponges long term. I tend to do better each time but it's still really tough. Even with adding additional food like phyto or stuff like that it's tough to provide enough without making our closed systems filthy. One thing that does seem to help is placement in our tank. Most of the sponges i've had don't seem to like a lot of light so i try to give them partial shade. For food, in addition to frozen foods like Rod's food that get broadcast around the tank, i also try to feed Oyster Feast and something like Reef Chili a few times a week. I'm not really sure how much it helps the sponges but I would think it would help a little. The sponges that do the worst for me are the deep red ball shaped ones that have a lot of layers to them. The ones that do better for me are the tall orange tree sponges and the little orange fan sponges. The yellow ball sponges fall somewhere in the middle. If you figure out any secrets let me know!