This water-element cultivation method was named the "Canghai Technique", created by Yunxiao Saintess, one of the three masters of the Sect of Cultivation, according to the teachings of the Heavenly Teacher Master, making it a water-element cultivation technique.
Lv Yue had some interactions with Yunxiao and had heard her lectures on the Great Path. He found this "Canghai Technique" to be quite extraordinary, so he studied it as well.
However, the real "Canghai Technique" contains fourteen layers, while the version Lv Yue had collected only had the first eight layers.
Nevertheless, even so, this "Canghai Technique" is an impressive method. The first eight layers alone could enable a cultivator to advance to the status of a true Immortal.
After much consideration, Lv Zhong decided that this current technique was most suitable for Dongfang Linglong at this stage, and thus decided to instruct her in it.