WHAT DOES MOUNT GAMBIER BLUE LAKE MEAN?

My companion and I are normal divers. We know in order to snorkel / dive at Pincanninie Ponds You'll need a permit. Are you able to dive while in the Blue Lake? If that's so where by is the greatest entry issue etc?I've got numerous nights camping and 1000s of kilometres of 4WD tracks around Australia less than my belt, and am always searching for