Suggest Treatment For Diarrhea

My toddler is starting on her third day of clay paste colored diarrhea, 4-5 times a day, sore bottom, does not seem exceptionally irritable, no fever, no abdominal tenderness. It started the second morning we were visiting a waterpark....she is drinking well, but appetite is definately on the low side.....should i be concerned since she is drinking well and no other s/s....the color concerns me too. After 3 days she is the only one in the family with this.