Conductivity and Water Movement
- Thread starter t.trezona
- Start date
What brand and how much of an issue?
Aside from water motion itself, bubbles and particulates may be more likely to get between the electrodes if there is a lot of flow.
Aside from water motion itself, bubbles and particulates may be more likely to get between the electrodes if there is a lot of flow.
Neptune. Probe calibrates correctly and reads 0 when dry and 53 plus or minus 0.2 using a Pinpoint 53mS std. When I put the probe in my sump water it reads 61. Using 2 different Refractometers the water measures to a SG of 1.026. If I put a specimen of tank water in a cup outside the sump it reads 54.8. RO/DI water reads 1.0 and back in the STD reads 53.3.
I think that 61/54.8 must be due to electrical interference rather than water movement.
Is the tank water grounded?
Is the tank water grounded?
fishflorist
CANNOT SPEAK ENGLISH
does your conductivity monitor have temperature compensation function ?
I have been confusing for many months since I bought a Pinpoint monitor, now I do not believe either monitor and refractometer. I dont know what to believe now.
I have been confusing for many months since I bought a Pinpoint monitor, now I do not believe either monitor and refractometer. I dont know what to believe now.
OK. I will try an electrical test with the system. With the probe in a paper cup of tank water well away from the tank I will connect a heavy guage wire from the tank water to the cup water. If the conductivity rises to 61 again then I must have a ground loop problem. Would that be correct?
I don't know exactly how to test for ground loops, but I agree that if you saw such a change, that would indicate a problem. I'm just not sure that the interface between a wire and the salt water will provide good conduction path for of the sort of AC signal that conductivity probes use.
OTOH, if you put some sump water inside of a glass container that is in the sump with the opening above the water line and measured the conductivity in that water while it was sitting in the same place in the sump, one could try to rule out flow and other interferences that went through the water. Electrical interference through the air and/or the electric cord itself is also sometimes an issue.
OTOH, if you put some sump water inside of a glass container that is in the sump with the opening above the water line and measured the conductivity in that water while it was sitting in the same place in the sump, one could try to rule out flow and other interferences that went through the water. Electrical interference through the air and/or the electric cord itself is also sometimes an issue.
The reference you quoted describes the test I mentioned. I will try the glass test tomorrow. However the glass test will eliminate both current and electrical issues. Will it not? What is confusing is why I would have any electrical interference with a grounding probe near the conductivity probe.
Yes, it will. Folks with some pH meters get their interference through the electric cord, as Jonathan mentioned.
