Joy, the Geo is creamy color, sleek and velvety when it shows up. It usually shows up before the PC and prepares the surface for stronger PC growth.
The Geo is slimy, wet; the PC is stark white and dry. They never fail to show up.
If you see that the PC recedes and creamy color reveals from underneath it, that is a sign that the Geo growth more than the PC. It should naturally happen later in the aging process (unless you made a thick fluffy white PC rind which isn't considered very good), but if it happens early on and you smell the beginning of ammonia, that means that the Geo is taking over. Reduce temperature and humidity if you want to slow down the Geo and accelerate the PC. Do the opposite if you get too much thick fluffy PC and you can't see the Geo.