How important is ORP?

[Andresnyc93]

Hello fellow reefers!

I’ve come across this subject many times but there doesn’t seem to be a clear answer on this so I’m wondering if someone here can explain why some people constantly monitor ORP? I’ve had mine set up since I got my first tank through apex but I’ve never really given it much thought since I don’t run ozone on any of my systems.
Is there a benefit for the livestock in our enclosed systems or is this a way to discard possible course of action in case something were to go wrong?

Thanks for the input!

 

[Randy Holmes-Farley Verified Community Expert]

The answer is clear (IMO) that it is not important to measure unless you need to be sure you are not adding too much oxidize substances such as ozone.

I discuss ORP in detail here:

ORP and the Reef Aquarium - Reefkeeping.com

 

[Andresnyc93]

The answer is clear (IMO) that it is not important to measure unless you need to be sure you are not adding too much oxidize substances such as ozone.

I discuss ORP in detail here:

ORP and the Reef Aquarium - Reefkeeping.com

Thanks for the quick reply randy! Will give this a read when I get home

 

[Subsea]

Hello fellow reefers!

I’ve come across this subject many times but there doesn’t seem to be a clear answer on this so I’m wondering if someone here can explain why some people constantly monitor ORP? I’ve had mine set up since I got my first tank through apex but I’ve never really given it much thought since I don’t run ozone on any of my systems.
Is there a benefit for the livestock in our enclosed systems or is this a way to discard possible course of action in case something were to go wrong?

Thanks for the input!

When I first starting Reefing, I used ozone and monitored orp.

While many reefers focus on pH swings during lights out, oxygen is a more critical parameter,

 

[J1a]

When I first starting Reefing, I used ozone and monitored orp.

While many reefers focus on pH swings during lights out, oxygen is a more critical parameter,

The problem is, orp has little to do with the dissolved oxygen in the tank. It's more affected by the amount of organics and species of ions in the water.

Speaking of which, @Randy Holmes-Farley , I believe ORP can be a reasonably useful proxy measurement for the abundance of organic compounds in the aquarium. It's not a well defined one, but is rather useful to gauge the rather unmeasurable organic level.

 

[WVNed]

It can tell you when you have done something stupid that you need to fix. Here is a graph from my Hydros controller.

There are actually 2 things here (the other was I turned the doser off) but the ORP probe shows what happened when I found I had stopped recirculation and flow on a sulfur denitrator a few hours earlier and turned it back on without thinking about it.
My ORP went to 40 from 300. There was a bad smell but that quickly cleared because I opened the door to outside.
I immediately moved large wavemakers to ingest air in the sump and bombed the system with bubbles.
The ORP went back up.
I am pretty sure this would have been real bad if the ORP had not alerted me to take action.

 

[Subsea]

The problem is, orp has little to do with the dissolved oxygen in the tank. It's more affected by the amount of organics and species of ions in the water.

Speaking of which, @Randy Holmes-Farley , I believe ORP can be a reasonably useful proxy measurement for the abundance of organic compounds in the aquarium. It's not a well defined one, but is rather useful to gauge the rather unmeasurable organic level.

I use an oxygen meter for the most direct measurement of system health.

 

[J1a]

I use an oxygen meter for the most direct measurement of system health.

Dissolved oxygen probe? That can offer plenty of insight to the dynamic of the aquarium.

What I have problem with though, is the location of the DO probe. The reading at different parts of the tank and sump can be quite a bit different.

 

[Andresnyc93]

It can tell you when you have done something stupid that you need to fix. Here is a graph from my Hydros controller.

There are actually 2 things here (the other was I turned the doser off) but the ORP probe shows what happened when I found I had stopped recirculation and flow on a sulfur denitrator a few hours earlier and turned it back on without thinking about it.
My ORP went to 40 from 300. There was a bad smell but that quickly cleared because I opened the door to outside.
I immediately moved large wavemakers to ingest air in the sump and bombed the system with bubbles.
The ORP went back up.
I am pretty sure this would have been real bad if the ORP had not alerted me to take action.

I have noticed too that when the gas exchange in the tank is not great the ORP will start having swings in the “normal” numbers within the tank and the ph levels also dropped, so I guess it’s a good form of measure on how well oxygenated you also have your system?

 

[Randy Holmes-Farley Verified Community Expert]

I have noticed too that when the gas exchange in the tank is not great the ORP will start having swings in the “normal” numbers within the tank and the ph levels also dropped, so I guess it’s a good form of measure on how well oxygenated you also have your system?

ORP responds directly to pH changes (lower pH gives higher ORP), so if you are looking at diurnal ORP changes, you might need to remove the pH influence if you think it is driven by additional factors as well.

 

[Andresnyc93]

ORP responds directly to pH changes (lower pH gives higher ORP), so if you are looking at diurnal ORP changes, you might need to remove the pH influence if you think it is driven by additional factors as well.

I was looking at the changes of the day time as well and have been trying to figure out a way to keep my ph stable. Problem is I have a bad air flow through the apartment I live in, so during winter times it’s hard to keep my ph at a stable rate and running a line to outside is very difficult since the tank is set up in a room that has no windows so I’d be basically running several feet of tubing to get some fresh air.

 

[fryman]

I feed alot of phyto and copepods. When doing so, orp drops. It recovers in a few hours. See example attached

When I first set up I never cleaned the probe so the orp reading slowly rose, until after a few months it was reporting over 400. After cleaning it settled back to about 300. I now clean all my probes monthly with citric acid and orp usually trends about 300. But I have no way to verify if this is even accurate.

I'm not sure these observation are useful at all.. I kinda ignore orp. I've considered switching it for another pH probe but I don't see a need for that either so it's just kind of there because it came with my apex.

 

[Andresnyc93]

I feed alot of phyto and copepods. When doing so, orp drops. It recovers in a few hours. See example attached

When I first set up I never cleaned the probe so the orp reading slowly rose, until after a few months it was reporting over 400. After cleaning it settled back to about 300. I now clean all my probes monthly with citric acid and orp usually trends about 300. But I have no way to verify if this is even accurate.

I'm not sure these observation are useful at all.. I kinda ignore orp. I've considered switching it for another pH probe but I don't see a need for that either so it's just kind of there because it came with my apex.

I’m on the same boat, only have it cause it came with my apex and I have noticed it drops when I dose phyto and also after a water change. Just wish they had a probe that was actually useful like perhaps a probe that measures elements instead of something not that many people have on their reefs like an ozone generator.

 

[HaveFishWillTravel]

Hello fellow reefers!

I’ve come across this subject many times but there doesn’t seem to be a clear answer on this so I’m wondering if someone here can explain why some people constantly monitor ORP? I’ve had mine set up since I got my first tank through apex but I’ve never really given it much thought since I don’t run ozone on any of my systems.
Is there a benefit for the livestock in our enclosed systems or is this a way to discard possible course of action in case something were to go wrong?

Thanks for the input!

Hello All, I’m not sure if my opinion will be popular or and I know that it won’t be as scientific as others, but here goes. I’ve had my APEX running now for ~18 months and I love it. The beauty of the APEX is that you can track what is happening in your tank over time Not only with the probes, you can also track the electrical current for your protein skimmer, for example. If your protein skimmer starts spinning, the APEX gives you a report that will tell you that very thing. With ORP, I think that people get confused by the “oxygenation”. What I think the ORP measurement does is it tells me whether or not the Nitrates in my aquarium are elevated thus, less oxygen.
The more Nitrates…the less oxygen.

The answer is clear (IMO) that it is not important to measure unless you need to be sure you are not adding too much oxidize substances such as ozone.

I discuss ORP in detail here:

ORP and the Reef Aquarium - Reefkeeping.com

I loved your article on ORP and in fact, I have seen it and I have read it multiple times. You are a very amazing guy and I very much respect your opinion.
I have an APEX w/my 4 probes and my other equipment is plugged into it giving me the opportunity to monitor the electrical current, which is also a nice feature. What I like about being able to see ORP is especially the way that APEX provides the reports that overlay one another. I can see over time what the Nitrates are in my aquarium or, lack of oxygen. I can see the fluctuations, for example, the way it goes up when pH is down and vice versa, which happens every day/night. What the APEX does is it provides a means to monitor and the aquarist can set alarms for when things go awry…when things are completely out of the ordinary. ORP is not a daily tool nor is the APEX. It is an over time tool and I find that it is helpful in monitoring the overall health of my aquarium over time. I am quite satisfied and happy that I bought the APEX and that I can see ORP because I have been away from my aquarium for months at a time recently and I still have the ability to see what is going on which gives me some solace. Not to the degree that I would like, obviously because I am not there and I am not maintaining it, but it still does have its value.
This is my $.02 on ORP and the APEX in general. JL

 

[Randy Holmes-Farley Verified Community Expert]

Hello All, I’m not sure if my opinion will be popular or and I know that it won’t be as scientific as others, but here goes. I’ve had my APEX running now for ~18 months and I love it. The beauty of the APEX is that you can track what is happening in your tank over time Not only with the probes, you can also track the electrical current for your protein skimmer, for example. If your protein skimmer starts spinning, the APEX gives you a report that will tell you that very thing. With ORP, I think that people get confused by the “oxygenation”. What I think the ORP measurement does is it tells me whether or not the Nitrates in my aquarium are elevated thus, less oxygen.
The more Nitrates…the less oxygen.

I loved your article on ORP and in fact, I have seen it and I have read it multiple times. You are a very amazing guy and I very much respect your opinion.
I have an APEX w/my 4 probes and my other equipment is plugged into it giving me the opportunity to monitor the electrical current, which is also a nice feature. What I like about being able to see ORP is especially the way that APEX provides the reports that overlay one another. I can see over time what the Nitrates are in my aquarium or, lack of oxygen. I can see the fluctuations, for example, the way it goes up when pH is down and vice versa, which happens every day/night. What the APEX does is it provides a means to monitor and the aquarist can set alarms for when things go awry…when things are completely out of the ordinary. ORP is not a daily tool nor is the APEX. It is an over time tool and I find that it is helpful in monitoring the overall health of my aquarium over time. I am quite satisfied and happy that I bought the APEX and that I can see ORP because I have been away from my aquarium for months at a time recently and I still have the ability to see what is going on which gives me some solace. Not to the degree that I would like, obviously because I am not there and I am not maintaining it, but it still does have its value.
This is my $.02 on ORP and the APEX in general. JL

Thanks.

why do you think that that what you are seeing relates to nitrate?

I do not think that ORP is impacted by nitrate, nor is it directly impacted by O2 levels.

 

[HaveFishWillTravel]

Thanks.

why do you think that that what you are seeing relates to nitrate?

I do not think that ORP is impacted by nitrate, nor is it directly impacted by O2 levels.

I think that it is the following sentence that I put into my previous post that might be the cause for your inquiry, “I can see over time what the Nitrates are in my aquarium or, lack of oxygen.”. I now understand your question. It took me a minute to figure it out. It was not exactly what I was trying to say, because I had narrowed it down to only Nitrates.
I oversimplified.

I think that the more things that die off or decay in your aquarium, the less oxygen in the water. Is this not true? Decaying live rock, fish waste and uneaten food contribute to less oxygen, increased temperatures and salinity will allow less oxygen to be saturated in the water. Here is my conclusion. Like I said in my post earlier, I have been away from my aquarium for long periods of time and I monitor my APEX ORP, pH, Temp, Salinity and electrical usage looking for spikes that don’t follow the normal everyday patterns. I am not looking at precise amounts on an everyday basis. What I believe the ORP numbers generally equate to is, less oxygenation in the water. There are many factors that can lead to spikes and drops and if there is a spike or it drops and stays that way after following a pattern for several weeks or months, it gives me a reason to take a closer look. This is especially important because I have been away from home for lengthy periods of time and the APEX is one of the ways that I am monitoring what is happening so that I can call someone to help. For example, if it is unusually warm and my aquarium is getting too hot, it needs to be addressed. If I am totally wrong, then, so be it.
I should not have said that ORP equates directly to Nitrates because that is not what it is.
The definition of Science is,
“…the intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment”.
This is what I’m thinking and whether or not ORP is a useful tool to you or others, is totally up to you. Not an exact science, for sure. I think that there is value in observing it.

 

[Subsea]

If I was starting over and was to choose which parameter was most important to monitor, it would not be orp: it would be oxygen. Orp is a secondary measurement.


After watching a 20 minUte video “Coral Reefs in the Microbial Seas”. Rohwer‘s statement that a healthy IndoPacific reef pH fluctuations was 8.3 - 7.8 was not detrimental to reef building corals but that reduced oxygen during lights out was contributing to declining reefs.

In the big picture what Rohwer postulated was that overfishing was removing grazing herbivores and that the DOC from algae as a carbohydrate was feeding oxygen consuming bacteria who smothered the coral.

 

[HaveFishWillTravel]

If I was starting over and was to choose which parameter was most important to monitor, it would not be orp: it would be oxygen. Orp is a secondary measurement.


After watching a 20 minUte video “Coral Reefs in the Microbial Seas”. Rohwer‘s statement that a healthy IndoPacific reef pH fluctuations was 8.3 - 7.8 was not detrimental to reef building corals but that reduced oxygen during lights out was contributing to declining reefs.

In the big picture what Rohwer postulated was that overfishing was removing grazing herbivores and that the DOC from algae as a carbohydrate was feeding oxygen consuming bacteria who smothered the coral.

I’ll check out the video, sounds interesting. Not only are the coral reefs perishing, but our planet’s largest rivers are now no longer sustainable. Salmon fishing is no longer allowed in Alaska on the Yukon River even for the Native Americans because of the 3 M’s (Mining, Manufacturing and the Military). It boils down to pollution which has led to Global Warming. Yes, climate change and yes, the climate is always changing, but man has chosen to exasperate it. Not meaning to highjack this thread…the Yukon River is over 1,800 miles long and in Alaska, it can no longer be fished. If you look at almost every single one of the rivers in another state, the state of Montana, they are suffering from drought. Agriculture is suffering, ranching is suffering and so are all of the people that the rivers support. Rivers are a lifeline just as the coral reefs are. Coral reefs are a barometer of what and how we are doing. No matter how you measure it, we are destroying it. As reefers, we all know how sensitive our few little gallons are. Think about the magnitude of pollution that must be happening to impact the reefs like we are doing. Just Sayin’