Why should I care about ORP?

[DiverGirl82]

I'm looking at getting a controller and I keep seeing that some of the higher end models come with an ORP probe. Can anyone tell me (in layman's terms) why I should feel the need to monitor ORP? At this point I kinda feel I can live without it.

 

[Coralz]

Not really needed unless using ozone but it can be helpful when using certain chemicals like chemiclean letting you know when the best time would be to redose etc.

 

[Randy Holmes-Farley Verified Community Expert]

It isn't needed. It is interesting to monitor, but won't make most aqauria better.

Here's my article on it:

ORP and the Reef Aquarium - Reefkeeping.com
http://reefkeeping.com/issues/2003-12/rhf/feature/index.htm

and here's the summary:

Recommendations for ORP

ORP is an interesting, if complicated, measure of the properties of water in a marine aquarium. It has uses in monitoring certain events in aquaria that impact ORP but may be otherwise hard to detect. These events could include immediate deaths of organisms, as well as long term increases in the levels of organic materials. Aquarists that are monitoring ORP in an aquarium, and are doing things that otherwise seem appropriate for maintaining an aquarium (such as increasing aeration, skimming, use of carbon, etc.) may find monitoring ORP to be a useful way to see progress.

ORP measurements are very susceptible to errors. Aquarists are strongly cautioned to not overemphasize absolute ORP readings, especially if they have not recently calibrated their ORP probe. Rather, the most useful ways of using ORP involve looking at changes in measured ORP.

Some aquarists use oxidizers to raise ORP. Those additions may be of benefit in some aquaria, and they may be beneficial in ways that aren't demonstrated by changes in ORP alone. I've never added such materials to my aquarium. In the absence of convincing data otherwise, such additions seem to me to have more potential risk than is justified by the demonstrated and hypothesized benefits.

 

[DiverGirl82]

Thank you both. I kind of thought it wasn't something I needed but now I'm convinced. It's not worth the extra expense for me personally.

 

[Randy Holmes-Farley Verified Community Expert]

You're welcome.

Happy Reefing.

 

[fab]

For those of us who are interested in monitoring ORP, please "riddle me this."

"What types of things might cause the short term rise and fall of ORP in a relatively cyclic fashion, say every few hours or so? For instance, something (???) happens and ORP starts to rise rapidly but in diminishing incremental amounts until it levels off as though in response to a step function stimulus. Then after a couple or a few hours from the start of this pattern it falls back down, abruptly and pretty much in a straight line, roughly to where it started. Then that pattern repeats 24x7.

fab
" Two things are universal, hydrogen and stupidity." Frank Zappa