ORP Reading ??

[jacob30]

My ORP reading changes about 100 Mv between day and night. Why does it do this? The change occurs seconds after lights turn on or off so this leads me to believe it is some kind of Electro magnetic influence on the probe. Any suggestions?

Last night it went from 428 to 340 Mv right afer the lights went out. Yesterday morning it went from 342 to 437 when the lights come on. These reading stay stable during night or day in their respective ranges.

Thanks in advance!
Jacob

 

[clp]

It sounds like the probe is picking up EMI from the ballast. Try the following:

- Since this is a 3 Pro, make sure that the temperature probe is within 6" of the ORP probe.
- Route the probe cords so that they are as far away as possible from the interferring ballast.
- Coil up any unused cords.
- Make sure the hood for the problem ballast is grounded.
- Ground your tank w/ a ground probe.

Curt

 

[jacob30]

Re-routed my orp cord and it has fixed the problem. Thanks for the advice.

Jacob

 

[Sparkss]

I normally only see interference when the MHs power up.. during their "firing" phase... but now I wonder if there is other residual interference that I am just not noticing....

 

[clp]

Look at the datalogs and see if the ORP changes signficantly when the lights turn off.

Curt