When I first started my refugium, I had the cheato too deep in the water (top of the cheato 4" below the surface) and I didn't get any growth. I put it up on some egg crate until the ball got large enough to rest on the rock below it. It grows like crazy now. I flip the cheato ball over twice a week, which helps also. When you do trim it (I just pull it apart with my hands), it is a good idea to spread out the remaining cheato, it tends to get so tightly pack together the insides do not get enough light.