Sometimes it takes a while to find the right food for your pup. Constant diarrhea simply means that the food you're using now isn't working either. Long Long Before I found EBN (and learned a bunch about foods, allergies, et. al.) my first pup was eating IAMS -- if you can imagine that. No wonder she had squishy poops and itchy skin. Poor angel. In contrast, Bea was on Orijin her first year and she had not one GOOD solid poop once. It was far too rich for her and Bo.
Can you get Natural Balance Duck / Sweet Potato? It's not the most highly rated food around, but it worked really well for my two for a long time. It's a limited ingredient diet --- so you can narrow down exactly what's going into your pup ---- so you can get you want to come OUT.