Actually i didn't miss it; but since the amount of merits gets lower everytime they are sent, we come back to my very first point.
Merit sources get some merits to spend every month. I think admin will increase the merit sources if needed. However, creating abundance of merits will not be a good idea. The system is designed in a way that with time, it will be very hard for spammers to survive here. The merits will revolve only among users who are here for contributing quality posts and want this forum to be full of useful resources.