ok i have to say this, no dog food, rice and hamburger, than go and tell them and insist that you see a doctor, it may not be ghiardia, it may be coccidia, it may be what bo mom said, it may be a lot of things for myself, i would dump that clinic you are going to, it sounds like the one i used to go to, the one i go to now, when i call they get me in, they know when i call it is not a false alarm,
i am worried becouse this has been going on quite a while, i would add pedialyte to his water so he does not dehydrate, that wont hurt him, but do not go from solid gold to nutro, that is just going to cause more distress to his system
solid gold and wysong are so much different from nutro that his system will not get better, i doubt this is from the SG
i would try to find a specialist if that worthless vet clinic is not going to help you.