We feed her Diamond Naturals. Our history with it was that she did excellent on it as a puppy. When she was ready for adult dog food, I asked our vet what he'd recommend for an adult dog food, and he said Royal Canin. We slowly transitioned to that, and she had terrible diarrhea and terrible bad breath that got progressively worse. So we just went with Diamond Naturals adult food at that time, and she was fine, other than intermittent tummy upsets we had attributed to other things (eating rocks in the yard, getting into some food in the kids' room). We adopted a second dog, and put her on the Diamond Naturals too. No issues. Now this spring, we sent them to a lady to board with for five days while on vacation, with a new bag of Diamond Naturals, and they both came home ill (diarrhea and vomiting). We weren't sure if it was stress, the flea and tick/heart worm treatment they'd just had, something they got into there, or what (they both went to the vet, had tests and stool samples, and both were treated but they never really pinpointed a cause).
They both were healthy again after a week, but I swear, ever since that boarding or since that new bag of their regular dog food, neither one of them really formed firm stools again. My one dog isn't having diarrhea, like I said, it's just a bit loose, but the shih tzu mix definitely is, I was up three times last night taking her out in the night. So I feel like maybe they changed the recipe of that dog food (we've bought several new bags of it since that boarding). They both did great on the wet food the vet gave them (Hill's Science diet canned weight control or something like that), but that is prescription only (I just checked at the pet store last night), and plus with wet food they don't get the teeth cleaning they do with dry.
I hope you're able to figure out something for your Pomeranian too!