Example of Apex Salt Probe Interference

Discussion in 'General Reef Discussion' started by Ben Nicholls, Jun 29, 2020.

  1. Ben Nicholls

    Ben Nicholls TCMAS Old Timer
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    My salt probe had been reading off. I know these are very sensitive to both air bubbles and nearby voltage lines. I decided to move the coiled up probe wire to see if it helped. As you can see it helped a lot. Looking at the graph I do see there was a bump everyday corresponding to my light schedule. After seeing that I realized that right on the other side of the wall are the transformer bricks for the lights. Mystery solved.


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  2. AsianReef

    AsianReef Former: 90ct
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    Can you explain more Ben? I have the same problem with my temp probe


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  3. OP
    Ben Nicholls

    Ben Nicholls TCMAS Old Timer
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    The temp probe is not really as sensitive to voltage interference as the salt probe.

    If the cord to the salt probe is near any voltage lines (like pumps, heaters, or lights), the power cord's electromagnetic field can affect the probe's readings. In my case I have most of my equipment in a closet behind the tank. There were no obvious power cords near the salt probe cord so I initially did not think that was the issue. What was happening is the light's power bricks are on the Tank side of the wall. Their electromagnetic field was strong enough to reach through the wall and affect the cord of the salt probe. Moving it about 6" resolved it.

    I didn't even realize the power bricks were close enough to bother it until after I move the cord and noticed the change. I then started investigating to try an figure out what would have been affecting it in the original spot. That's when I noticed the value increases every day in the graph which correspond to my lighting period.
     
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  4. HouseofStark

    HouseofStark I contributed!
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    Happens every night when my H380, fuge light turns on... I have separated wires ran the H380 light out the front of my stand and across room, still happens

    Neptune said yep, they have seen it happen through walls. I just work with it... besides that its super stable...So I leave well enough alone
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  5. AsianReef

    AsianReef Former: 90ct
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    Thanks for your input Ben. And I meant my salt probe btw lol.


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  6. OP
    Ben Nicholls

    Ben Nicholls TCMAS Old Timer
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    At least it is regular and only about a 0.5 change.

    I'll probably calibrate mine again since the cord is now away from the interference. When I originally set the tank up the power bricks were on the floor of the stand. Last year I decided to get them away from potential water spills and mounted them on the wall behind the tank. Interesting how small changes like that can affect seemingly unrelated things.
     
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