You suck at growing chaeto? That's about the only thing I can do right in my tank. That stuff grows like a weed in my fuge. I pull a good size handful out every couple of weeks. I got mine at my LFS, I asked if they'd sell me any and they said, "no, we'll just give you some, this stuff grows so fast it's no problem." They gave me about a softball sized chunk and it quickly grew to fill up my fuge in no time. Oh, and to further answer the first posters question, the main purpose that chaeto fills is to suck the nitrates out of your water. That's it main food source so to speak.