I have been using a coffee bean grinder on corse setting with AM 500 pellets, then I sort the larger chunks from the smaller ones with a stainless steel strainer. It has worked well for feed training two size classes of RES from last years spawn. I have them in two different tanks, in one tank they are 3/4" to 1-1/2" and in the other tank I have 2" - 3"+. At this point I think I will end up with 70-80% of the six dozen RES that I have pellet trained.