I tried various things. Even added a CAPTCHA to stop bots from registering. Now I’ve turned on moderation of registrations, all new registrations have to be approved by me. Hopefully that will slow it down. I’m open on taking suggestions to improve the PHPBB forum software if anyone has experience with it to stop spammers. Any Add-Ons or Plug-ins?
I’m also trying to clean up old registrations that spammed before but that process is going slowly. If you want to become a moderator and help let me know. Few of us doing this may be faster.