I was playing around with this the other day, and hard 8mm pellet as well. What I found is that the carp responded best to little and often feeding, but they were feeding in the last 6 inches of water. My theory was the the lightness of the bait made it waft around, so what I did was to have a strung out shotting pattern with about 8-10 inches of gap between the droppers. I started dead depth then shallowed up by half an inch each put in until i started catching. Lifting and dropping, etc and then settled on catching about 2 inches off bottom. But the key is i think is to move your shotting around or change hooklengths and keep making little changes until you start catching, its all in the little details.