Peakhour integrates the OWASP Modsecurity core rule set.
This ruleset aims to protect against a wide range of attacks including the OWASP Top Ten with a minimum of false positives. This ruleset is recommended for all websites.
Internally Owasp gives every incoming request a score to determine the action to take. The higher the score the more of a potential threat the request is. By setting the inbound anomaly level low you will make the firewall block more requests.
With each paranoia level increase, more rules are applied giving you a higher level of security. However, higher paranoia levels also increase the possibility of blocking some legitimate traffic due to false positives. If you use higher paranoia levels, it is recommended you first place the WAF in warning mode to enable you to disable rules that are generating false positives for your site.