How many days is sugegsted to travel in Beihai?

When I was there, I spent about five four days. I spent one day near local Beibuwan Square, where you can find architectures in many styles. Silver beach cost me two days. To be honest, if I have more time, I would stay there for another day. The beach area is perfect.
The last day I went to Weizhou Island.
I tasted the seafood in Silver beach, but I think it was expensive. The local people think Jinsheng Meishi Restaurant on Banpo Guizhou Road is good.

Thank You Bob ! This is helpful... could you give me some tips on how to get to Weizhou Island, and how much time i need to allocate for Weizhou. How to get to Silver beach and which part of the beach is best? Safe to swim there, or is it full of jelly fish?

From Beihai Internatioanl Passenger Port, there are ferries for that island and the timetable is 08:30, 11:15 and 16:00 in general. There are two kinds of ferries to reach the island. The fast ferry costs around an hour and the low ones cost around two to three hours.
The timetable is not certain, so it is suggested to make sure and book the ticket in advance one day before.
For the Silver beach, you can take a taxi to reach in about 15minutes. All the places are very nice. I did not see the jelly fish there, but I think swiming there is fantistic.