1)
What is "Tzidon Rabah"?
1.
Radak: It was the populous Tzidon. There was a smaller Tzidon.
2)
What are "Misrefos Mayim"?
1.
Rashi, citing Targum Yonasan: They are furrows [near] the sea. They make furrows, and sea water enters them, and the sun evaporates it, and salt remains.