I have been pacing my battling so that I never hit 100% ECR. I complete lots of battles in the morning, more in the middle of the day and then lots more at night before going to bed. The good part was that last night I was on a winning streak but then this morning I lost 12 in a row. I was able to earn 6 silver loot chests. I was so happy when I saw that Chaos pack and a rare card. I hope tomorrow will be just as good.