In Shab Qadr, the water of the seas becomes sweet
Among the signs of Shab Qadr, it is also said that this night the water of the oceans becomes sweet. Imam Razi (May Allah shower His mercy on him) has related an incident of the ocean water becoming sweet on the 27th:
Translation: Hadhrat ‘Uthman bin Abul A’as (May Allah be well pleased with him) had a slave. He told him: In Ramadhan, there is a night in which the water of the ocean turns sweet. When the night came, he informed me and it was the 27th night of Ramadhan. (Mafateeh Ul Ghaib, Surah Qadr-1)
There is Tradition in Tafseer Qurtubi that in Shab Qadr, the water of the oceans turns sweet:
Translation: Hadhrat ‘Ubaid bin ‘Ameer (May Allah shower His mercy on him) says: I was traveling through the seas on the 27th night of Ramadhan. I drank some water from the sea and found it sweet and tasty. (Tafseer Qurtubi, Surah Qadr-1)