You've clearly done zero research on this topic. Merits don't decrease, 100 merits doesn't mean anything, and you can't coerce anyone to send merits to someone else, but with 100+ merit sources and thousands of other merit-sending users you just need to participate in the forum - not "so that [you] can get more merit" but genuinely take part in discussions - and you'll get those merits.
Except you don't even need them... you can happily post without merits like thousands of users did before merits even existed.