[Anonymous]

Nutrisca salmon and chickpea, no grains, no potato is bland and works well for my dog that has a sensitive stomach.
Wysong has some nice selections too.
I just use the kibble as a base and add something/homemade.

Occasional loose/soft stools are one thing, but watery, runny diarrhea (more than 72 hours) can lead to dehydration. Look at some of the feeding tips in that homemade diet link I provided, maybe something he says will be helpful.