As for the energy production that the other two hundred and more half-step fifth-grade Spirit Pets add to the Grotto Heaven, it's actually secondary.
Thus, the growth speed of the Phantom Clone's Grotto Heaven is faster than that during Li Shiming's time.
Of course, the most important factor in all of this is the Great Power level 'Chaotic Spiritual Power' within the Phantom Clone. Once the radius of the Grotto Heaven reached ten thousand meters, and the internal space reached the extreme limit of a half-step Great Power, the energy within the Grotto Heaven increasingly approached the level of the Great Power.
The Great Power level 'Chaotic Spiritual Power' within the Phantom Clone allowed the cultivation of the 'Yuqing Thunder Scripture' to produce Thunder Attribute Spiritual Power that was infinitely close to the Great Power level, and thus the energy within the Grotto Heaven was also infinitely close to the Great Power level.
