Help dealing with spam logic

[akyeame]

I have a blog, and i have decided to use Akismet and reCaptcha for spam filtering, the way i am dealing with spam isa) the user should go through the captcha before posting a commentb) Now even if some spam bypass captcha then i would like Akismet to handle it. For akismet to handle the Spam, i thought of creating two different tables in database for comments, One to store the comments which is not detected by Akismet , The other is to store the Comments that is detected by akismet(Spam). the reason behind this logic is i thought may be i don't want to mess my comments table with spam so only i thought of storing the Spam detected messages in different table.Now the problem is duplication of table will exist if i use this methodology. instead i could add an extra column in the table to check and store wether it is a spam. i could do either way. which one will be wise to adopt. ?