Please get rid of your log-ins for comments.
You would have triple the comments if you got rid of them. What's the point of creating an obstacle to comments? In my experience, the systems never work, and Blogger, for example, never lets me on, despite having signed up properly a year ago. If you want comments from our team of brainiacs, get rid of those dang nuisances.
Just delete obnoxious or unwanted comments or trolls - it's like vacuuming the house. No big deal.
Just reading the anti-spam letters is tough enough - I cannot even read my own - X and K and H are indistinguishable.