My 11 year old Odin is having the same issues. Initially, we attributed it to the heart worm meds, but then it started occurring at different times of the month. Even though he was making puddles, he had no urgency. He looks to us like he has lost weight. Like you, we tried many things. Last week, our vet had us tried Hills WD and it worked! We now have him on Hills Chicken and Barley, which you can buy over the counter at the pet store or on line. It also seems to be working, but, time will tell. So far, so good! Good luck with your grey.