Lcvod HaRabbanim, b'h
I learned in Tamid that the Kohen at the beginning of the avidah would have to raise the kior from the waer in which it was submerged.
This was becuase the water in the kior would become pasul b'linah if left out over night. But I also learned that this pasul occurred at daybreak. And then after he used the water he lowered it again, and then the next kohanim would have to raise it again. So my question is : if the pasul didn't happen until daybreak, and he was starting the avodah before that, so why not leave the kior up for him, and then he could lower it after he used it - in preparation for the kohanim after him? Thank you. R.A. Rosen Sfat*When* the water in the Kiyor became Pasul is a Machlokes Amora'im in Zevachim (21a). According to Rav Chisda, which is the Shitah you quoted that the water becomes Pasul only at Alos ha'Shachar, Tosfos asks why they bothered to lower it at night. He answers that they were afraid that if they left it they would be negligent and not lower it.
D. Zupnik