Two temp probe two different temps.......

SPotter

SPotter

Active member
I'm posting this question here because apparently I don't have proper security clearance to post on the GHL Site Forum. So since switching over to GHL I haven't been checking things like water temp and ph as closely as I used to when I had an Apex. Well tonight I'm getting getting ready to do firmware upgrades and noticed that the temp in my display reads 78.5 but the temp in the sump that's 25ft away is reading 80.6. So I get out my temp controller that I use for when I'm making water and proceed to test my frag tank, live rock tank, sump and display with both the GHL probe and temp controller. On the three tanks in the fish room I got readings of 80.4 to 80.6 with the GHL probe and with the temp controller got temps of 81 in all three tanks. I brought the temp controller in the house and put it in the display where the GHL probe is reading 78.5 and the temp controller came back at 81. I checked my connections, moved the probe into the display instead of the overflow box and still read 78.5. I checked the probe to see if there wasn't anything on it or looked out of the norm and that was fine. Now I take the probe from the fish room and swap it with the one on the display....no change. I'm trusting the GHL reading of the three tanks in the garage and the reading from the temp controller. So what's wrong with my temp probe #1 reading? Is it possible that it's picking up electronic interference from my MH ballast since they are in the same area? My chiller has been set to temp probe #1 and while my temps are over the top crazy they're definitely a lot higher than where I'd like to keep them.

Some pics to illustrate what I'm talking about.....

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Put as much ice that will fit in a glass then fill with water then place the probe of the temp sensor in the ice water it should be 32 degrees this is common practice for testing probes in my industry.
 
chrishvacman said:
Put as much ice that will fit in a glass then fill with water then place the probe of the temp sensor in the ice water it should be 32 degrees this is common practice for testing probes in my industry.
Click to expand...

sounds like a fun experiment but not really sure what good that does?
 
I think this goes beyond a probe being bad as I mentioned above, I swapped the probe that was plugged into my expansion box in the fish with the probe plugged into the main control unit and still had the same temperature readings. If one of the probes was bad I would expect the temp reading in the fish room to have the lower reading and the display tank to have the higher reading.

I appreciate your suggestion and will still try it out of curiosity.
 
Yeah I failed to thoroughly read your post kinda skimmed it lol. I bet as you suspect some kind of interference is affecting the temp reading I bet your probes are not shielded most are not and they are picking up some kind of inductive interference.
 
chrishvacman said:
Yeah I failed to thoroughly read your post kinda skimmed it lol. I bet as you suspect some kind of interference is affecting the temp reading I bet your probes are not shielded most are not and they are picking up some kind of inductive interference.
Click to expand...

I still like the experiment and will try it :spin3: I guess its a little redundant to have two temp probes and as long as one is operating accurately I will base the heating and cooling on that probe. I decided to have two probes because half of my water volume is in my garage where the temperatures out there are very different from inside. But I recently added a mini split system in the garage for cooling and heating so I can effectively maintain the same temps in the garage as I can inside the house. Would still like to hear from GHL on this. I finally gained access to their forum and have posted this over there as well.
 
There is an offset option in the temp setting screen you can adjust that, but for sure the industry accurate way of testing a probe is ice water.
 
AQD_ottawa said:
There is an offset option in the temp setting screen you can adjust that, but for sure the industry accurate way of testing a probe is ice water.
Click to expand...

thank you for jumping in here Michael. do you have screen shot showing the offset option? I was looking for that last night and do not see anything that would allow me to manually adjust the temperature. There's about whether or not the probe is working properly as I believe it is. There's either something wrong internally with the base controller or is it possible that its picking up interference from other probe lines or power cords for other equipment that's causing the reading to deviate?
 
I dont currently but Vinny the tech support guy can chime in here.

To eliminate interference remove the controller from the tank area and re-locate
 
I understand I could move the controller from its current location but my question is whether or not the probe could be picking up interference from something else in the area causing the deviation in temp reading. Are these probes vulnerable to electronic interference? I looked for information in the user guides but nothing is indicated. If they typically don't pick up on interference causing deviations then I don't want go thru the hassle of relocating the controller.
 
steve switch it to expert mode. calibration and temp adjust will show up under the other menu. its in the view tab.

I use ice water and hot tap water and do the calibration and adjust the values so they match up with an old school thermometer
 
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