The always seem just a a little chewy no matter how long i have them on?
I sometimes have that problem--but just keep drying, maybe "blast" at a higher temp for a few hours. Also, as they cool they may harden up. If it continues to be an issue, maybe your atmosphere is quite humid, and/or you need to slice thinner. Finally, when i was working with a smaller dehydrator with less power, i would "cure" the mostly-dried pieces in a very low oven for an hour. If you are worried about spoilage, as I sometimes am, keep with a silica gel pack, or store in the freezer in a safe container. My dehydrated veggies and fruits have lasted well in all circumstances, even with a varied degree of crispness.