Use SpringServe's auto optimization to reprioritize your waterfall. In the Optimization tab of a supply tag, enable optimization and select your parameters. Optimization runs every 20 minutes and uses the parameters you specify to reprioritize your demand tags.
Optimization parameters can be set on multiple levels:

Optimization Metric:

Lookback Minutes: the number of minutes the adserver looks back to make an optimization decision

There are no boundaries on the lookback minutes. You can choose 10 minutes or 5000 minutes or more.

Notes on How to Select your Optimization Parameters

A poorly performing tag that is low in your waterfall has trouble climbing back up.  It must compete against the tag in the next lowest priority and produce better results, which is rare. Much of your decisioning about how to use these settings depends on a number of factors:

Additional thoughts: