Surah Al-Furqan Verse 53 - English Translation by Almuntakhab Fi Tafsir Alquran Alkarim
Surah Al-Furqan۞وَهُوَ ٱلَّذِي مَرَجَ ٱلۡبَحۡرَيۡنِ هَٰذَا عَذۡبٞ فُرَاتٞ وَهَٰذَا مِلۡحٌ أُجَاجٞ وَجَعَلَ بَيۡنَهُمَا بَرۡزَخٗا وَحِجۡرٗا مَّحۡجُورٗا
And He is it Who sent the waters of the two seas flowing together, one fresh and sweet and the other salty and bitter and between both He installed an invisible partition which serves as an impassable barrier (the fresh water floats above the salty and there are laws that govern the separation and the depth)