You don't need a
@ tag if you're responding to the owner of a post. It is discouraged, and thus removed upon submission.
The first author of the question or answer will always be notified of any new comment. There is no need to use @name to notify them. (You may still use it for clarity, if needed; however if only you and the author have been commenting on the post so far, the @name will be automatically removed from the beginning of the comment, as it adds no value.)
Further explanation here:
@lerting the post owner in a comment is not necessary. If comments are only between you and the post-owner, and nobody else is commenting, then an @lert to the post owner at the beginning of a comment will be removed.