Editing PH meter (section)

===Maintenance===
Because of the sensitivity of the electrodes to contaminants, cleanliness of the probes is essential for [[accuracy and precision]]. Probes are generally kept moist when not in use with a medium appropriate for the particular probe, which is typically an aqueous solution available from probe manufacturers.<ref name=magub/><ref name=mrc/> Probe manufacturers provide instructions for cleaning and maintaining their probe designs.<ref name=magub/> For illustration, one maker of laboratory-grade pH gives cleaning instructions for specific contaminants: general cleaning (15-minute soak in a solution of bleach and detergent), salt ([[hydrochloric acid]] solution followed by sodium hydroxide and water), grease (detergent or methanol), clogged reference junction (KCl solution), protein deposits (pepsin and HCl, 1% solution), and air bubbles.<ref name=mrc>[http://mrclab.com/media/uploads/ph_electrode_maintenance.pdf MRC lab: How to Store, Clean, and Recondition pH Electrodes] {{Webarchive|url=https://web.archive.org/web/20150922044420/http://mrclab.com/media/uploads/ph_electrode_maintenance.pdf |date=2015-09-22 }}.</ref><ref>[http://www.ph-meter.info/pH-electrode-cleaning Cleaning electrodes].</ref>