What is the frequency of the stools? If less than 3 per day you need not worry.
What is the solid food you are giving? Was it newly introduced after which he developed the change in stools?
is okay. Unless it is watery and very frequent, you need not give ORS
Continue breast feeds, Give him rice based foods, vegetable soups and curd. Curd naturally has the probiotics seen in sporlac. Give him lots of curd daily..
Hope you find my answer useful.