Calibration looks OK.
According to Christian Buil's webpage
spectrum of domestic
energy saving lamp (bright red line), my spectrometer is almost spot on (my reading of 6113A line is 6119A).
So, Rocolax filter does pass 6560A Halpha line.
For my measurement I used LED (which has a pretty broad spectrum around 656nm), and measured the wavelength of the (sharp) edge introduced by IR stop filter.