I think it's hard to find a grain free food that doesn't have potatoes because they need something to bind it all together to form the kibble.
Acanas grasslands use to just have sweet potato (which I don't think is the same as white potatoes for aggravating arthritis) but now contains russet as well. So, to get away from both potato and grains is pretty much impossible.
I see that Darford does have some buckwheat but I imagine its the peas and pea starch that serves to bind it all together. The last time I tried a food with pea starch was Horizon and it really did smell like peas when you opened the bag. My dogs didn't really like it so I'll be interested to see what this is like.
I'd go back to a chicken and rice but is there anything out there that has higher meat content with a smaller amount of rice???