My Four Month Baby Has Reflux According To His Pediatrician.

My four month baby has reflux according to his pediatrician. I've tried four different formulas all Similac brand except one, nutramigen. None of them seem to help him in anyway. The last one was the worst caused him liquid diarrhea and now I'm back to the beginning on Similac sensitive. He doesn't cry it is cause him to spit everything up. Do you have any advice on anything else to do or any specific formula of a different brand to try? I've heard goats milk may be better. Do you have any suggestions?