[Pi]

I got this from a friend. Still in the box but was wondering if the bulb is toast. If I buy the calibration solution(s) do you think it is still ok?

[hugh_jass]

Put the unit in a solution e.g. distilled white vinegar to know whether the unit is operational before buying the buffer solutions. If the pH drops to expected values then move to the next step and buy the buffer and storage.