Hello! Just this morning I picked up my sulcata tortoise (I am guessing she is around 7-8 months, I received her in May of this year) and inspected the underside of her shell. I was surprised to see those dark little half circles near the bottom as just a few weeks ago I checked her underside and they were not there. After this photo I did softly wash her shell and most of the dirt came off, but the half circles still remain. Does anyone know what this could possibly be from? I give her calcium sprinkled on her food 2-3x a week, she has uvb and heat bulbs, soak her religiously everyday, but sometimes the humidity fluctuates from 50-80%, typically staying around 70% on most days. Could the humidity be a problem? Not enough calcium? Please let me know, thanks!