Musnad Ahmad 1153:239

Yahya narrated to us, from Musa al-Juhani, who said: They brought a bowl during Ramadan, and I estimated it to be eight, nine, or ten ratls. Mujahid said: Aisha narrated to me, "That the Messenger of Allah (peace and blessings of Allah be upon him) used to perform ghusl with the likes of this."