Carboy on left contains 5 gallons of Apple Cider, yeast nutrient, pectic enzyme and White labs "WLP720 Sweet Mead/Wine Yeast".
Carboy on right contains 5 gallons of Apple Cider, yeast nutrient, pectic enzyme and White labs "WLP715 Champagne Yeast".
Both carboys were put together at the same time. Both show signs of yeast action in the air lock, but one seems a bit more active than the other.