Different Temp Reading

[camreef]

So these morning i got an alert from Apex that my temp drop to 74-75F and it time for me to go to work so i just grab a spare heater and throw it in, what i already have in my tank is cobalt 75w and the spare one is that 100w. All day i still got same alert and temp still the same so i though my temp probe might fail while i do have a new one. I put them both in same chamber of the sump and it read the same temp, then i try in my DT it show 76 and i try again in the heater chamber it read 81F. Anyone ever facing that ??? I have an Eshopp Cube Nano sump.

 

[Crabs McJones]

So these morning i got an alert from Apex that my temp drop to 74-75F and it time for me to go to work so i just grab a spare heater and throw it in, what i already have in my tank is cobalt 75w and the spare one is that 100w. All day i still got same alert and temp still the same so i though my temp probe might fail while i do have a new one. I put them both in same chamber of the sump and it read the same temp, then i try in my DT it show 76 and i try again in the heater chamber it read 81F. Anyone ever facing that ??? I have an Eshopp Cube Nano sump.

So you put both heaters in the sump and the temp didn't change, and then you put it up in the display tank and the temp rose according to your apex? Am I understanding that correctly? Where is the temp sensor in your system? Before or after the heater chamber in your sump?

 

[camreef]

Normally my temp probe is in Refugium of my sump and the heater in Skimmer compartment, first i put new temp probe in refugium compartment also and temp reading the same, so i move that temp probe to the DT and temperature reading is 76F it like 2F from refugium compartment then i move that temp probe back to skimmer compartment where heater is and it read 80F. It seem like the heater only heat the water in that compartment and it just happen like that today, normally it wasn’t like that

 

[jda]

Get a glass thermometer with mercury in it - trust these over anything electronic. Temp probes are not all that reliable and sometimes need calibrated often - the probe could be measuring differently based on position (wires or probe are worn out).

Also, display temp is all that matters - measure from there.