User blog comment:B214/Question and Answers 6/@comment-185.112.105.215-20161103101120/@comment-106.68.185.19-20161103143717

As far as I know, Sona's power is nothing in comparison with Rias' Power of Destruction. She's quite adept and all, but she's more into techniques and tactics.

Anyway, in volume 21 it is shown that she is skilful enough to manipulate the sea.