Given that there are reports that the current actual number of merits given in the past months did not meet the expected merits for circulation, please let me propose an idea.
Give an incentive to the Merit Sources for them to be proactive in achieving their quota.
This will serve as a positive reinforcement to the Merit Sources to encourage them to attain the quota of number of merits for circulation for the month (or for a given period).
Not only this would be pretty much abused just like said above, merit sources would also be forced to give out what they have. If this happen, sources may give undeserving members merit which literally destroys the purpose of the system. I say let the sources give those who they deem worthy.
An incentive can be a form of payment (bitcoin?), special privilege (additional feature on their profile?), or anything that is beneficial to them.
Monetizing the merit system? Hell no.
Additional feature on profile? I think this would remove the anonimity of the merit sources, which is also unlikely.