I’m always surprised at the brightness of LED light sources these days. Most people think that the brighter the excitation light is, the brighter the signal will be, and they are used to setting the irradiance to 25, 50 or even 100%.  But for both the pE-300ultra and the pE-800, I constantly need to recommend starting at 1 or 2%, which will produce plenty of signal, and can always be increased.