Here in Slovakia we call it like "water level flowstone" - but it would be complicated to name for this symbol. So is the "disc-stalactite" OK in English?
I can only speak for what I have heard in the UK. We call these "pom poms" after a famous stalactite called "The Pom Pom" in South Wales. (In turn, this is named after the thing cheerleaders hold.) I imagine that in the USA they will use a completely different name. However, we don't really seem to have a generic name for the effect. The rafts that float are called "calcite rafts", but the ones that are stuck to a stalactite at the water's level don't have a formal name that I have heard. Maybe someone from the BCRA could say... "Water level growths" is probably as good as anything, but far too long for Therion.
Another symbol: point plus|minus|plus-minus currently, for "plus" and "minus" there is: point height -value + point height -value - and there is no symbol for point +-. So I suggest to add "point height -value +-" and make a circle version of point height.
There is already a +- round text ornamentation. It is used whenever the p_label_mode is p_label_mode_passageheightposneg, which I think is only "point passageheight:both". Tarquin