ORP (Oxygen Reduction Potential)

Good Morning All,

While I'm not new to the hobby, I am however re-entering the hobby after a 14 year hiatus. I am preparing to start-up a 90g tank and have been progressing at a somewhat slow pace. I have purchased most of the start-up equipment and I am at the point where I will be adding the live rock and sand within the next two weeks. I have been following the threads in the forum and I have read several threads concerning various controllers/monitors. I have noticed that ORP is monitored by these devises and my question/s is this;

1. What is the importance of monitoring this area (ORP)?
2. What does Oxygen Reduction Potential actually mean? Is it a process? What is actually happening?

Thank you,
john1948

 

as I have never monitored mine, I cannot provide as much information as other people... but for a little bit of basic information:
It measures the reduction potential of your tank... aka how fast organic molecules are broken down. Since oxygen is an excellent electron acceptor, it willingly takes up electrons from all metabolic processes (photosynthesis and oxidative phosphorilation). so the higher your ORP, the quicker your waste is dissolved by bacteria. I believe levels are between the high 300's up to 500... but not positive?

 

Oxidation Reduction Potential (ORP). Measured in millivolts (mV) - it is a measurement of your waters' potential to oxidize contaminants. It is basically an indication of water quality.

If you run Ozone you need to measure ORP to be able to properly introduce ozone to the aquarium, but it's not directly related.

 

The bottom line is this. Unless you run Ozone, there is no real reason to monitor ORP.


ORP can vary a lot, but usually is in a wide range of acceptable readings.
By the time your ORP would go insane on a non ozone running tank, your critters will probably all be dead.

If you have money to spend on an ORP sending unit/ probe and at least a way to monitor it, go for it, but I don't know a single reefer that uses any ORP monitor, and the guys in my local club have some insane setups of over 1000g's

 

i agree w horkn
i think that good protein skimmers help orp

 

You basically have a rough baseline in your tank

Protein skimmer not skimming efficiently, ORP will start dropping
Clean that protein skimmer, ORP will rise back up
Overfeed, ORP will drop
Fish died somewhere in your tank, ORP will drop

The reason it's confusing to people is because they see any drop from baseline as bad. That's not true. If you add another fish, your ORP is going to drop. However, if you haven't overstocked your tank, that is just your new baseline. It's more about trends over time as opposed to a reading at a single point in time.

 

Thanks Everyone, I get it. I love this forum.

 

Redox on wikipedia. Some of the more nitty gritty.