My Son Is 1yr 2mnths He Has Been Having Very

my son is 1yr 2mnths he has been having very frequent as often as 7-10 diapers with loose and mostly scant amounts of stool that are very acidic, his eating and sleeping habits have not been affected yet i cant seem to find something that will harden stools such as fiber, eating apples or dry toasts and rice cereals, any suggestion on what the potential problem may be? he is drinking whole milk yet this is something he has done since 10 to 11mnths old he adjusted to this and stool had become regular after adjusting to the change.