ORP down to 365 from 420, does it mean something

[balajeek15]

I have the ORP probe with my neptune system which usually read around 450+ range but looks like recently following downhill and its around 350 now.
I read about ORP a while ago and didn't get it to understand clearly. So does this decrease mean something i need to take care or check any parameters.

 

[taricha]

Just noting how much smoother the data was for the early values makes me think I would check the sensor.

 

[rkpetersen]

Decreasing ORP can mean that something has recently died and not been removed.
Or it can mean that your tank is building up organics in the water, not removed by skimmer, GAC, water changes, etc.
However, a drop in ORP is also very common with doing water changes with some salts, even small water changes.
Also, some common additives, including products that contain ferrous iron (Fe+2) or ascorbic acid (vitamin C), will also depress the ORP reading.
So a drop in ORP is really quite nonspecific.
It can indicate bad things happening, but can also just be due to normal maintenance procedures.

 

[balajeek15]

The drop is been over a week, if it a maintenance issue wouldn't that will be on that day.
I will do all the test this weekend and see what's up. from my last week test all seem ok though. I am not sure if ORP sensor need regular calibration.

 

[SuncrestReef]

Last year my ORP was dropping quite a bit over about a month but I was never paying attention to it. Many of my corals started receding. After several died I started doing a lot of water changes and I noticed quickly how ORP was rebounding to normal levels. I now pay a lot more attention to ORP.

I can’t say for sure that was the cause of the coral problems, but I’ve seen the corals looking consistently healthy when ORP is higher.

Here’s my last 7 days:

 

[User1]

What do people even do with the ORP reading and what is a good range. Honestly it is one of those things that is there with the controller but I do not pay one bit of attention to it. I know it is usually 300 - 320 range though.

 

[taricha]

What do people even do with the ORP reading and what is a good range. Honestly it is one of those things that is there with the controller but I do not pay one bit of attention to it. I know it is usually 300 - 320 range though.

Necessary if you Ozone.
Otherwise, as an alert that things might be going badly somewhere.

 

[rkpetersen]

What do people even do with the ORP reading and what is a good range. Honestly it is one of those things that is there with the controller but I do not pay one bit of attention to it. I know it is usually 300 - 320 range though.

400 is often considered a target ORP level.
To get there without ozone, you'll generally need pristine water with minimal organics, a not-too-heavy bioload, no overfeeding, and not using salts or other products that depress ORP.

 

[MnFish1]

What is your pH? has that risen? ORP can fall with an increase in pH - or as others have said if there are added decaying elements, added chemicals to the water, water changes, or most likely - a dirty or starting to get dirty probe (algae, etc). I have found them to be a bit unuseful. But - rapid changes with no other cause may lead you to look for other sources of decay, death, etc.

 

[User1]

Thanks. That makes sense. I do not run ozone so that probably explains why I just sort of look at it as a early indicator for something

 

[Randy Holmes-Farley Verified Community Expert]

What do people even do with the ORP reading and what is a good range. Honestly it is one of those things that is there with the controller but I do not pay one bit of attention to it. I know it is usually 300 - 320 range though.

IMO, there’s no desirable ORP target range, except you do not want it getting excessively high when using oxidizers such as ozone.

 

[Angrywalnut]

Apex just alerted me the ORP was under 200. It was 350 before feeding. I was in the yard at the time and fed the tank an hour earlier(Phyto). The skimmer came back on after the 1hr delay and overflowed causing Orp to tank. It was at least 2 pints of skim mate that went back into tank so it definitely reacted to the "dirty" water.

 

[Jay Z]

Orp probes will start to degrade in performance over time. It’s actually cheaper to buy a new probe then to buy the stuff to recalibrate.

Running no socks and ozone makes it go out way faster.

When in doubt, clean it. Soak it in vinegar/water for 20 minutes or so, brush it with a tooth brush, repeat again. Then soak in distilled water for 5 minutes to reactivate. I run 3 orp probes with my ozone. I need to clean them every 4-6 weeks, my apex is about every 2 weeks. Milwaukee’s seem to hold true a lot longer than the apex one in my sump. But my apex is in the next chamber ahead of my Milwaukee’s.

They can get calcium build up and gunk on them over time.

My apex one would hold true for 5-6 months at a time before I kicked the ozone on. Now it gets dirtier way faster.

And I have noticed orp swings with water changes and feedings. Mine drops 3 times a day from my awc.

First pic is my apex probe when the water change happened to now.

Second is my actual reading now.

 

[rkpetersen]

It’s actually cheaper to buy a new probe then to buy the stuff to recalibrate.

Nope.

Lab Grade Double Junction ORP Probe

Neptune Double Junction probes will out last most other traditional lab grade probes letting you go longer between calibrations, and having to purchase and replace probes less frequently. The Double Junction isolates the reference gel and probe from proteins and other organics that may otherwise...

www.bulkreefsupply.com

Sensorex B125 6 Piece ORP Calibration Solution Kit: Science Lab Electrochemistry Accessories: Amazon.com: Industrial & Scientific

Sensorex B125 6 Piece ORP Calibration Solution Kit: Science Lab Electrochemistry Accessories: Amazon.com: Industrial & Scientific

www.amazon.com

 

[Jay Z]

Nope.

Lab Grade Double Junction ORP Probe

Neptune Double Junction probes will out last most other traditional lab grade probes letting you go longer between calibrations, and having to purchase and replace probes less frequently. The Double Junction isolates the reference gel and probe from proteins and other organics that may otherwise...

www.bulkreefsupply.com

Sensorex B125 6 Piece ORP Calibration Solution Kit: Science Lab Electrochemistry Accessories: Amazon.com: Industrial & Scientific

Sensorex B125 6 Piece ORP Calibration Solution Kit: Science Lab Electrochemistry Accessories: Amazon.com: Industrial & Scientific

www.amazon.com

Sorry I was off $4

 

[Randy Holmes-Farley Verified Community Expert]

Apex just alerted me the ORP was under 200. It was 350 before feeding. I was in the yard at the time and fed the tank an hour earlier(Phyto). The skimmer came back on after the 1hr delay and overflowed causing Orp to tank. It was at least 2 pints of skim mate that went back into tank so it definitely reacted to the "dirty" water.

It reacted to the low ORP materials in the skimmate, not to the dirtiness of it. Many organics will have no immediate impact on ORP, but some, such as antioxidants like vitamin C, will drop ORP like a rock.

 

[Randy Holmes-Farley Verified Community Expert]

For those who want to understand more about what ORP is and is not, i discuss it in great detail here:

ORP and the Reef Aquarium - Reefkeeping.com

http://reefkeeping.com/issues/2003-12/rhf/feature/index.htm

 

[balajeek15]

Thanks for the article, its an in-depth and I am not sure if i understood all of it but somewhat enough. Ultimately the reason could be multiple things and hard to pin point. I always had a steady reading of around 460 for a long time, and it was very clean tank back then with Nitrate 0 and Phos 0 at that time, I started to bring that up from 0 to 5 on Nitrate and 0 to 0.02/0.03 on Phos, by dosing and more feeding which makes the tank a tiny bit dirty. Not sure if that could be the reason to see decrease in ORP reading.

Also while inspecting i noticed my skimmer not bubbling and no skimming, and i suspect the skimmer pump and the equipment need cleaning which i plan to do is asap. I will update ORP reading on the result after skimmer return to normal.

Or could be a reason that i added 2 piece of Real Reef rock (like an arc), I understand its man made rock and no dead stuff in them.

thanks all.

 

[Montiman]

I would not worry about ORP unless using Ozone. I use ozone so I pay attention to it. The last time it alerted me to a non Ozone related problem was when I saw ORP drop to 80. I thought the probe was bad so I replaced it and got the same reading. Started searching everywhere and found that my BioPellet reactor had clogged and the flow rate was really low. Cleaned it out and the ORP went back to 350. ORP is not very specific and no value is good or bad but when the value changes it means something has changed and if you don't know what changed then you can try to find out if something happened. Every time I dose amino acids the ORP drops 200 points which is fine because I know what triggered it. I get worried when it drops and I don't know why.

 

[thatmanMIKEson]

For those who want to understand more about what ORP is and is not, i discuss it in great detail here:

ORP and the Reef Aquarium - Reefkeeping.com

http://reefkeeping.com/issues/2003-12/rhf/feature/index.htm

I think I'm finally learning to decipher the code in your articles and information