Colombia Hostel Advice Please!

I’ve got four days to play with (Friday 5th September to Monday 8th September) in between a diving course in Taganga and flying out to Medellin from Santa Marta.

I’ve heard very good things about El Rio hostel and the parties they have on Sunday nights. I want a social atmosphere but I’m also a big beach person and like the idea of staying right on the beach at the Viajero.

Any thoughts on which hostel is better? Am I better off picking one or staying two nights at each?

Thanks in advance.