Is CleanTalk Compatible with Cloudflare?
CleanTalk is fully compatible with Cloudflare service.
The CleanTalk Service doesn't filter Cloudflare's IP's (AS13335) with blacklist database. That means the CleanTalk module will filter spambots using other anti-spam tests and checks.
SpamFireWall option by CleanTalk works properly with Cloudflare as it takes real IP's of website visitors from HTTP headers.
More details of how SpamFireWall option works are here: