How old are those probes? I'd look into replacing them.So I bought a used apex and this I got the probes and they are just coated in crap…. Anyone have any suggestions as to safe ways to clean them without messing up the probes? Is citric acid safe?
Apex says to replace at certain intervals. Although pricey. Start replacing 1 at a time, just disable ones not in use then enable as you replace.