What to do for prolonged jaundice?

Does anyone have any advise or experience of baby with prolonged jaundice? My son is 1 month plus old already. His jaundice levels is still within the 200 plus range. Previously, he had a 24 hour phototherapy at kkh, which helps to bring down to 100 plus. But then the jaundice levels slowly crept back up the week after. When back to kkh and did a series of blood tests, and all is okay though. So I recently tried to do mixed feeding of 1 to 2 fm a day. I also bathe him in the yellow flower water and bring him for sun tanning. But it does not seem to help. He still sleeps a lot and he still looks yellow. What else can I do? Should I change to full fm?