I guess the drain number is the result of resting the 50k steem- xk steem spent = -21,666 steem, it means there was more steem spent in payout, not 21,666, this number is the drain... When this number get to 0, we could say there is no drain (equal number of steem spent and added to the pool)... I would like to see this drain number every day to get an idea of what the drain rate is, it should probably stop in the next week or so...