Each stage Core condensation stage involves doubling the size of the core. For example, if the core in the early stage was formed from a thousand drops of liquid spirit qi then the core in the mid stage would have to double its size and reach two thousand drops of liquid spirit qi.
Subsequently, in the late stage, it would double again to reach four thousand drops and then finally eight thousand in the peak stage of the core condensation realm. The amount of spirit qi drops was not the same for everyone and depended on the size of their dantian.
The cultivators that were more talented had higher capacity, while those that were less talented had lesser capacity. Any cultivator that reached the core condensation realm could live for a total of three hundred years.
