ORP handheld meters

[AquAttila]

I am looking to purchase one of these handheld ORP meters and wanted to see if anyone had used before and if specific one is better for salt water aquarium. Seems that many mention pool

 

[KrisReef]

Interesting question. I bought an cheep meter for my RODI and I have always wondered how reliable the numbers are I get. Same with pH handhelds. Hopefully people who know how these work and how reliable they are (or arn't) will supply a reply to your question.

Bump I am supposed to be in the Office but I haven't left yet!

 

[AquAttila]

thanks... yea, I run ozone and my ORP just does not make sense as it was showing 350+ for months and then suddenly dropped to 160ish. I suspect the probe, but they are expensive and would be great to have a reliable way to check on Ph, ORP before replacing the probe on apex.

 

[KrisReef]

thanks... yea, I run ozone and my ORP just does not make sense as it was showing 350+ for months and then suddenly dropped to 160ish. I suspect the probe, but they are expensive and would be great to have a reliable way to check on Ph, ORP before replacing the probe on apex.

This makes sense.
Do they make a standard solution for comparison/ calibration that would help indicate when it is time to replace?

 

[AquAttila]

nope. It seems that ORP probes are calibrated at factory and not something that requires calibrations. I watched the BRS video on this and that is also what they stated. I am not sure if I should be chasing after ORP as everyone seems to say don't worry about it. However, I can tell you when my ORP was at 350+ the water was crystal clear so know ozone was working.

 

[GARRIGA]

Bought the HM Digital model. Only used once and haven’t checked against reference to validate reasonable accuracy yet have several different handhelds from them and trust what they produce overall. Lots of good reviews. Their TDS meters used by BRS. I’m one to stick with companies I trust based on prior experience.

 

[Tavero]

nope. It seems that ORP probes are calibrated at factory and not something that requires calibrations. I watched the BRS video on this and that is also what they stated. I am not sure if I should be chasing after ORP as everyone seems to say don't worry about it. However, I can tell you when my ORP was at 350+ the water was crystal clear so know ozone was working.

That's probably their way to increase sales. ORP are built similarly as pH electrodes meaning they are measuring against an internal reference solution. If the reference changes the results change as well. You can get standard solutions at 200mV 400mV and 600mV.
Edit: the mostly used standard seems to be 256mV