SlopeCharts is on a ceaseless pathway of improvement. Today’s new feature is color volume bars, which has been an oft-requested upgrade. You can find the toggle for this over in the Preferences dialog (the gear icon on the extreme right of the tools).
Checking this box will create red volume bars on down days and green volume bars on up days. You can also change the height of the volume pane by dragging the horizontal up and down. Here I’ve stretched it rather high so you can plainly see the colored bars (oh, sorry – – ‘bars of color”):
And here it is in the context of a stock chart.
Color Volume Bars