I found some old Hypo Check tonight. Being out of it otherwise, I wondered if there was a way to see if it still worked. I put out normal chemistry, played with a few prints and tried a drop of Hypo Check in the fixer - no precipitation. So I figured I was smart (G), and directly poured some developer into the fixer...thought that would kill the fixer. Hypo Check still did not react. So I wonder if Hypo Check reacts to fixer exhaustion more than contamination directly from developer.
Is there a way to check proper function of Hypo Check?