Digital Thermometer Mystry Solved

Okay,

So I have a Lifegaurd big display digital thermometer that has water and ambient air temperatures. I had the probe in the water and the display set on the edge of the tank stand. The water temperature was always accurate to the glass and stick-on thermometers. I recently built a hood and mounted 6 T5 lights from retrofit kits in the hood and with the added height I could no longer set the display on the edge so I attached it to the from of the hood. For some reason the temperature would jump at least 2 degrees up which caused the alarm to go off for my high temp of 80. If I moved it down off of the hood it would read normal. I initially thought that the probe wire was defective or shorting out. I then got my digital turkey probe out and put that in the water and it started to jump all over the place. I then started to think of what else could be affecting the display and I thought that the only other change was the addition of the lights, sooooo, I unplugged the lights with the temp display still mounted on the hood and the temp reading dropped to the expected temperature. SO, this means that there is some kind of interference being given off by the T5 lighting that is causing this fluctuations. Anyone have any ideas? The ballasts are mounted on the outside of the hood on the back and they are grounded. The reflectors are not grounded, would that possibly create some electrically charged IONS to be bouncing around? I do have a grounding probe in the sump but not in the DT as my thought was that they are connected by the flow of the water back and forth through the return and drain lines.

Has anyone else notieced this before or is it happening and people were not aware?

Looking for your .02!

Thanks!

Joe

 

Never thought about it but i will have to keep an eye on my digital thermometer's form now on when i make changes.

 

T5s give off a lot of noise and can cause problems like this to PH probes and anything really that is using a remote probe.

Great troubleshooting It would have likely taken my $1000.00 and months to figure that out

 

Thanks! +k