ORP is Practically Useless!

[CindyKz]

Also, we had a thread where someone noted a pH effect due purely to temps outside (cold fronts showed a rise in pH), and I posted a study that showed there was more natural leakage/convection through a home in terms of air turnover if the air temp outside was much lower than the air temp inside.

Cold, fresh air leaks in at lower levels, warms up and gathers CO2 along the water, and leaks back out again at higher levels.

This will be really interesting to watch as the seasons change here in WI.

Santa brought me an Apex (early) and the ORP probe is still in the box. As Randy pointed out, we don't even know if it impacts the life in our tanks, so I don't see a point in looking at it. It would just give me something to freak out about.

 

[Sharvey103]

The value of ORP in determining the content of water is greatly enhanced if the user has some knowledge or history of the aquarium. ORP data can typically become more useful if used as an indicator over time and/or with other common parameters to help develop a complete picture of the water quality being tested.

 

[Flameback Pair]

If I had a skimmer with a variable speed DC pump I would control pump speed with the ORP reading. When ORP starts swinging downward, the Apex can pick this up and adjust the skimmer's pump speed down to account for the increase in organics and lower water height in the reaction chamber to prevent an overflow and also save money by drawing less amperage. When ORP is really high, speed the pump up as there is less organics in the water, and it takes a higher water level in the reaction chamber to raise the foam head higher in the cup, therefore less skimming is necessary. So as the level of organics ranges in a concentration spectrum, the protein skimmer's DC pump speed can be adjusted to coincide with the need of skimming performance. High organics => low speed. Low organics => high speed. Just my $0.02. B-)

 

[splix]

I only monitor it because I have the probe from when I was running ozone. Might as well use it, doesnt cost me anything. I dont have alerts or watch it like it's important though, it's just there.
It's cool to see when a clean up crew member dies though. I had a sharp dip a couple week ago and saw that one of my hermits killed a conch for it's shell. ORP went back up a few hours later. Just this week a turbo died and it showed up on the ORP graphs. Mine normally hits the floor at 300 and climbs to 330 at night.

 

[Randy Holmes-Farley Verified Community Expert]

If I had a skimmer with a variable speed DC pump I would control pump speed with the ORP reading. When ORP starts swinging downward, the Apex can pick this up and adjust the skimmer's pump speed down to account for the increase in organics and lower water height in the reaction chamber to prevent an overflow and also save money by drawing less amperage. When ORP is really high, speed the pump up as there is less organics in the water, and it takes a higher water level in the reaction chamber to raise the foam head higher in the cup, therefore less skimming is necessary. So as the level of organics ranges in a concentration spectrum, the protein skimmer's DC pump speed can be adjusted to coincide with the need of skimming performance. High organics => low speed. Low organics => high speed. Just my $0.02. B-)

Have you specifically noticed that lower ORP means more foam at fixed pump speed in your system?

Lower ORP does not necessarily mean more organics.

 

[XNavyDiver]

Agree 100% on ORP
Must say, imho, the Apex Salinity monitor seems equally useless

Agree on the ORP thing, but my salinity monitor is spot on.

 

[Flameback Pair]

Have you specifically noticed that lower ORP means more foam at fixed pump speed in your system?

Lower ORP does not necessarily mean more organics.

I have noticed this.

Has anyone noticed ORP going down when there's fresh fragging glue in the tank?

 

[CindyKz]

The value of ORP in determining the content of water is greatly enhanced if the user has some knowledge or history of the aquarium. ORP data can typically become more useful if used as an indicator over time and/or with other common parameters to help develop a complete picture of the water quality being tested.

Used as an indicator of what, exactly? The little bit of reading I've done (granted, it hasn't been much) doesn't support ORP as a reliable indicator of any specific value. My take-away is that ORP as an indicator of organics in the water (or anything else) is conjecture at this point.

 

[trido]

Agree on the ORP thing, but my salinity monitor is spot on.

Do you have apex classic with the module or the new 2016. My classic Sg probe was great, my 2016 Sg probe is useless.

I use ozone daily, regardless of whether I run it a few hours, or 24/7 it does not raise my Orp. For me the probe is also useless but I would not remove it.

 

[trido]

I have noticed this.

Has anyone noticed ORP going down when there's fresh fragging glue in the tank?

No I have not. I grow and make upwards of 50-100 frags at a time. If there is a drop it’s from coral slime and not the glue.

 

[XNavyDiver]

Do you have apex classic with the module or the new 2016. My classic Sg probe was great, my 2016 Sg probe is useless.

I use ozone daily, regardless of whether I run it a few hours, or 24/7 it does not raise my Orp. For me the probe is also useless but I would not remove it.

2016. I've never run ozone myself.

 

[ca1ore]

The value of ORP in determining the content of water is greatly enhanced if the user has some knowledge or history of the aquarium. ORP data can typically become more useful if used as an indicator over time and/or with other common parameters to help develop a complete picture of the water quality being tested.

Ok, perhaps you can share those actions you have taken as a consequence of changing ORP numbers.

 

[ca1ore]

Except that people open windows more when temps are suitable and less so when it is too hot or too cold.

Also, we had a thread where someone noted a pH effect due purely to temps outside (cold fronts showed a rise in pH), and I posted a study that showed there was more natural leakage/convection through a home in terms of air turnover if the air temp outside was much lower than the air temp inside.

Cold, fresh air leaks in at lower levels, warms up and gathers CO2 along the water, and leaks back out again at higher levels.

This seems more correlation that causation, but I'm just a business guy so what do I know. Certainly more fresh air enters the house when the temperatures are favorable, however, measuring outside temperature and triggering some kind of action to practically affect pH based on that reading (my interpretation of what the poster was suggesting) seems arcane to me.

 

[Randy Holmes-Farley Verified Community Expert]

This seems more correlation that causation, but I'm just a business guy so what do I know. Certainly more fresh air enters the house when the temperatures are favorable, however, measuring outside temperature and triggering some kind of action to practically affect pH based on that reading (my interpretation of what the poster was suggesting) seems arcane to me.

I wasn't suggesting that one should take action based on outside temps, just that pH in a reef tank inside can respond to outside temps.

 

[csb123]

Except that people open windows more when temps are suitable and less so when it is too hot or too cold.

Also, we had a thread where someone noted a pH effect due purely to temps outside (cold fronts showed a rise in pH), and I posted a study that showed there was more natural leakage/convection through a home in terms of air turnover if the air temp outside was much lower than the air temp inside.

Cold, fresh air leaks in at lower levels, warms up and gathers CO2 along the water, and leaks back out again at higher levels.

I certainly could not have said it better.

I’m just saying pH monitoring is not a very power tool.

On the other hand, alkalinity monitoring gives real actionable intelligence. I can’t wait for the technology to be refined and the price to come down.

 

[Ferrell]

I'll preface this by saying I have a 3 month old tank and a 2 month old apex good parameters.
Since hooking up apex with all probes including ORP I've noticed ORP drop when I added 5 new frags and when I did water change, downward in both instances. Outside of that.... Not much use except for steady readings and that's why I'm reading these articles. To find out if I should be worried.