sprkplug -I've had the same concerns for AM 600 for the last 8-12 yrs that you are seeing with AM 400 & 500. I wonder about their Quality Control, My concerns have even been present even before they remained their trout chow and tweaked the formula to Aquamax. I've talked to company reps several times about the inconsistant pellet size, pellet color, and the way it absorbs water. Each bag in my experience is a little or noticably different as Sprkglug is saying. I get excuses from Purina such as availability of raw products and when the extruders that produce the pellets have been cleaned last. I think some other manufacturers have better quality control and a more consistant which is why some professional trout farmers prefer brands other than Purina. Purina has invited me to vist the pellet manufacturing plant in Richmond IN. They evidently give tours.
