Pinpoint Conditivity monitor changes with location and touch

[aroundtuit]

I've been trying to find an answer to the subject in a couple of other forums. I first tried the Marine Depot Forum under the sponsor Forums, since that is where I recently purchased the monitor. After no response there, I posted it in the Newbie Forum , since that fits me quite well. There, it was suggested to me that this might be the best place to ask, so here I am.

Originally posted by aroundtuit
I recently purchased a Pinpoint Conductivity Monitor and a PH Monitor. Just tonight I noticed something strange with the conductivity monitor while checking my freshwater tank. As I bring my hand near it, the reading will change by 30-40 microSiemens. Also, it will vary wildly depending where on the tank I set it. On top of the lights, it will go well above 600. If I set it on the glass top, near the end of the light, it will drop under 300. If I set it off to the side away from the tank its near 500.

Are the readings affected by interference from electrical devices and other objects near it or is it possible I have a defective monitor? I would have expected the cable to be shielded to prevent any such interference.

Anyone else experience this?

[thackray]

Tuit,

That meter is sensitive to stray electrical fields. Many people need to take a sample out of the tank to get a good reading. Also, it will probably work better running off the battery instead of the adapter.

You may have some electrically leaky equipment in your tank. Put EACH piece of equipment which is submerged on it’s own ground fault circuit (GFI) and ground your tank with a titanium probe (Marine Depot).

Phil

[Randy Holmes-Farley]

I agree that it may be due to interference due to excessive emissions from the lights. I'd measure away from the lights, or when the main lights are off.

Here's a thread on how the pH probe has such issues:

http://archive.reefcentral.com/forum...hreadid=344393

[Bryan]

FWIW I have the same problem with the Pinpoint Salinity monitor.

[Fastmarc]

Originally posted by Bryan
FWIW I have the same problem with the Pinpoint Salinity monitor.

Same here for the Salinity monitor. In my case, I think it is the lights.
I solve this by taking out some water and testing it.
It might suit you to do the same.

[Boomer]

Are you guys running them on AC or DC batteries. AC often causes problems, so batteries usually work best, as Phil has mentioned. Any of you using Fluro lights ? Something Phil maybe can explain is the cord not being straight but wrapped up or overlapping that causes induced voltage between the cords. You will see this sometimes in audio systems, same with the hand. Hands wrapped around some cords act like a shield.

[Fastmarc]

Battery here.
When I installed a grounding probe, it helped a bit, but it would still fluctuate a little if I dipped my finger into the tank.
When the lights are off, it seems ok.
Just to be sure, I still take the water out and measure it.

[aroundtuit]

I'm using the battery, not an a/c adapter. And when I turn the pc lights out, it becomes very steady, less than 2-3 microsiemens variation.