What is the timing accuracy of ancient clepsydra?

Thanks to the unremitting efforts of scientists in past dynasties, the technology of leaky pots has been greatly developed, which raises an important question for us to study the leaky sculptures in China: What is the timing accuracy of ancient leaky pots? This is a seemingly easy problem to practice. Although many people have done a lot of work, no consensus has been reached so far. Of course, there are also many difficulties objectively. For example, the ancient clepsydra is still intact. (There are only three clepsydra handed down from the Western Han Dynasty, one set in Yuan Dynasty, two single pots in Yuan and Ming Dynasties, and one set in Qing Dynasty. ) Carved arrows are mostly made of bamboo and wood, and few have been handed down from generation to generation. It is not easy to imitate the ancient water, the operation procedure is not easy to do, and so on. Therefore, it is difficult to estimate the accuracy of clepsydra through simulation experiments. Only in the 1950s, the leaking kettle in the Jiaotai Hall of the Forbidden City was tested, and the result showed that it leaked 3.5 kilograms per hour and 84 kilograms per day, with a 24-hour error of about 10 minute. This is our general understanding of the accuracy of clepsydra in Qing Dynasty.