i have 2 14month old terrapins, both are shedding skin at the momoment, is this normal? they are feeding fine and swimming about still, they dont look ill BUT the water keeps going powdery white so i have changed it twice yesterday - only to find it cloudy again today, i have taken them out now - but what can i do :? also i found some white stuff round the males mouth and on his head, are they ill???? please help cause im worried :/