Jim Ginn,
Axis range depends on multiple factors like y-values of dataseries attached, other chart-options like includeZero, interval, minimum, maximum, etc. In your case, multiple dataseries are attached to secondary y-axis that includes range of values from 0.18 to 281. Hence, auto calculated axis minimum includes a negative interval. Setting minimum: 0
should remove negative values in this case.
—
Vishwas R
Team CanvasJS