An embodiment of a method for adjusting system gain of a biological probe array scanner for a plurality of fluorophore species is described that comprises setting an excitation beam comprising an excitation wavelength at a first power level that elicits an optimal signal to noise ratio response from a first fluorophore species; scanning a biological probe array with the excitation beam; setting the excitation beam comprising the excitation wavelength at a second power level different than the first power level that elicits the optimal signal to noise ratio response from a second fluorophore species; and scanning the biological probe array with the excitation beam.