Hi Robert-
Sorry to hear about your pup. I had the same issue with my pups. It took a very long time for their tummies to get back to normal after a long bout with giardia. The link that acroyali gave you has some helpful information. I used some of the supplements that are suggested on that site and found them helpful. Although some of them are quite expensive too.
Have you tried a VERY slow transition to a new food? Like maybe over a two week period to get fully to the new food? I still often use Perfect Form and/or probiotics when I start a new brand of kibble.
Victor grain free Hero formula was the first kibble that they actually did really well on. I now rotate it with Whole Earth Farms, TOTW, and NutriSource. Let me know if you have any questions on supplements. I used Gastriples and Vetri Pro BD and though they were helpful. I hope this helps!
