Subtract two series -> graph scale does not adapt

I subtract two series stored in InfluxDB and plot the difference series in a graph grouped in 15m intervals.
However, the scale of the graph seems to align to the two original series that I don’t even want to show in the graph.
Is there any way to get around this?
I’m using Grafana v5.0

what I mean is the following:
I subtract series 2 from series 1

when I only display the difference series, though, the scale doesn’t adapt and I can barely see the values.

is there a solution to this problem?