Is there a limit on the number of Block Sites i can add to the Blocked Sites Keywork List?

Trying to find out if there is a limit to the number of domains i can add in the blocked sites list on an Netgear Nighthawk RAX75.  There does not appear to be a limit set in the documentation, but it does appear to have one when i reach a X number of keywords.  It will stop adding them to the list.  I'd like to know what that number is if anyone has that information.