Hi Mark,
As has been said many times before on here, there are a number of factors involved such as previous feeding of the fish, water temps and protein content of the bait. My suggestion, as ever would be not to put too much pellet in and work on catching one at a time. They are much easier to catch when they're hungry.
People will have numerous stories of the time they "filled it in" and had a red letter day. What people (probably the same ones) don't say, is how many times they've failed by doing exactly the same thing, not only spoiling their chances of catching anything for days but also any chance for others fishing the same strech!
Hemp and maggot/caster is easier to use in reasonable quantity than pellets or boilies due to the protein content and digestability of these baits.
I would also consider what everyone else is putting in on the strech. I catch most of my fish in the summer months on single 17mm pellets or boilies because other people are chucking in shedfulls of pellets and boilies.
Hope that helps Mark?
Regards,
Jeff