I use a combination of pine shavings, pelleted sawdust, and peat moss. I have about five or six inches of bedding down now. It has built up over several weeks. My maintenance routine is to lightly rake fresh droppings off the top of the bedding in the morning (it goes into the garden or compost), stir all the bedding to get air into it, and sprinkle fresh shavings on top. I use straw in the nest boxes, which I change out when it begins to get moist.
In the veranda, where the water dishes are, I use pelleted sawdust mostly. I have sand over hardware cloth. I lay down a layer of pellets, and when that seems damp through, lay down another layer. Then once a week (or two, depending on weather), I rake out the dirty sawdust and spread it over the garden or put it into a compost pile.
One advantage of keeping some deep litter is that you can let it build up a little more in the late autumn, and if it works well, there is a bit of composting action in the bedding, which produces some heat and helps keep the ducks warmer in winter (as well as being insulation on the floor).
I like the DE idea. Need to try that out. Noticeable difference?