[adwade]

My guess is you need something to show you who's a spammer and who's not offhand. My advice would be to install a MOD that will ferret out such accounts. Something like vBStopForumSpam.

Next, or actually FIRST, I'd recommend installing something to KEEP unsavory spambots OFF your website automatically. I say 'first' above, because I'd want to stop the tide of spam immediately and ZB BLOCK is a very easy/fast install, plus it's FREE too! :up:

Lastly, I've had MUCH BETTER luck with the Q&A Human Verification over the CAPTCHA methods, so I'd recommend giving it a try.

I certainly hope this helps, because 17,000 accounts is an awful lot to go through!