Soul Storm the ENTIRE 20 minutes.

Simply put, soul storms should amp up rather than clearing completely after 3 generators get destroyed. It sucks to only be able to run a single set of generators online when it gives the most sought after loot, every 40 minutes. Not to mention even if you have a full set of corrupted gear, soul storms provide one of, if not the best source of echo shards even with this devious 100 shard cap.