Use the Ammonium ISE to measure levels of ammonium ions introduced from fertilizers. It can also indicate aqueous ammonia levels if sample solutions are acidified to convert NH3 to NH4+. The Ammonium ISE has a combination-style, non-refillable, gel-filled electrode. Like all other PVC ISE membranes, the membrane on the ISE has a limited life expectancy. However, the replaceable module of ISE allows you to simply discard the used membrane module, and replace it with a new one. Probe must be used with a Vernier interface (i.e. LabQuest and LabQuest Mini) or a computer with Vernier software. Click link for Vernier software tutorial