Without any filtration, one could simply roll around in the Dragon Pool and take on the form of a real dragon. But, such a weakling possessing the appearance of a real dragon, even if it improves its physical abilities significantly, would still be readily slaughtered by its foes.
A pack of useless fish and shrimp, masquerading as true dragons, being brutally slain by the enemies of the Dragon Clan; how could the Dragons bear such humiliation? Thus, a great war was born from this.
Who knows the price the Buddhist Gate had to pay to let the Dragon Clan tolerate the existence of Dragon Pool, but the Dragon Clan had strict regulations on its use, demanding that scaled creatures transforming in the Dragon Pool possess a certain degree of discipline.
They could be weak, or different from actual dragons, but they could not take on the image of a true dragon only to be effortlessly slaughtered.
"So, did I break the agreement between your Buddhists and the Dragon Clan?"