Spam filter list reach maximum

I have my spam filter list turned on, obviously.  When I select an email and mark it as spam, I get a message that says: "Total number of spam filter list entry reached maximum value 5..."

First I cant even read the whole message.  Apparently this should automatically generate an email back to me with the whole message.  Outside of that, How to I increase the "maximum value" to be 900Gb ?  Whatever it is, it needs to be huge.