Honestly, kung grayish na ang poop, I'd suggest checking with your pedia muna kasi that's not typical and might mean something needs adjusting sa diet or formula, hindi basta brand switch lang ang solution! A few of us tried going to Similac or Enfagrow, pero talaga ang best gatas really depends sa tyan ng bata mo, and your doctor can check kung may lactose intolerance or other issues na nangyayari. What did your pedia say when you noticed the color change?