Hi, my 9 year old beagle dog has been on prescription c/d
science diet pretty much his whole life. The doctor recommended it because his PH levels in his urine were high. He's never actually developed crystals or bladder stones, perhaps the prescription diet prevented this, not sure.
Anyway, throughout his life, he has always had soft stool. It was either diahrea or soft stool, but never hard. It's likely why he has chronic anal gland infections.