Massive spam users and spam entries despite triple layer protection
I recommend you try something different from the usual enter text Captchas. 


  I personally use Are You A Human module. This is a video tutorial on how to set it up: Drupal 7 Are You a Human PlayThru
  Module - Daily Dose of Drupal episode 78.


If you want another option, I suggest you try Draggable Captcha here is an instruction video on how to set it up Drupal 7 Draggable Captcha - a more friendly way to prevent Spam 

A new one that came to my attention is reCAPTCHA. Uses the Google reCAPTCHA web service to improve the CAPTCHA system and protect email addresses.