Is an ORP probe really all that useful?

Daniel@R2R · Jun 27, 2017

I'm planning to replace the ORP probe on my Apex with an additional pH probe which will run my calcium reactor. I'm debating whether or not I should invest in an additional pm1 module so I can run the ORP probe...but I honestly haven't seen where ORP is really all that useful. I read @Randy Holmes-Farley's article on ORP, and from that it doesn't seem to be helpful as a reading. ...but in the spirit of debate, I thought I'd post the question here. How do you guys use ORP readings, or do you generally ignore them mostly? #apexusers #ghlusers

evolved · Jun 27, 2017

It's only useful when watching for trends, and the practical use of those trends is if ORP creeps up, then your nutrients are getting low. Of course, the contrary is also true, but the more practical use of a low ORP is if it suddenly plummets. This could indicate a possible emergency situation, but more commonly in established tanks an invert spawn triggers a low spike.

I kept mine and use a PM1 for the CaRx, but it's only an overly cautious move. If you tend to never look at or pay mind to your ORP numbers, it's probably of little difference for you.

AdamNC · Jun 27, 2017

From what I understand about watching Orp is it's really only useful if your running ozone.

wmo168 · Jun 27, 2017

So the # keep going up to 398-400 I need to change water?

d2mini · Jun 27, 2017

evolved said:
It's only useful when watching for trends, and the practical use of those trends is if ORP creeps up, then your nutrients and getting low. Of course, the contrary is also true, but the more practical use of a low ORP is if it suddenly plummets. This could indicate a possible emergency situation, but more commonly in established tanks an invert spawn triggers a low spike.

I kept mine and use a PM1 for the CaRx, but it's only an overly cautious move. If you tend to never look at or pay mind to your ORP numbers, it's probably of little difference for you.

4 out of 5 dentists (plus me) agree.
I initially got mine to run/control ozone. When i'm not running ozone, it's just as stated above.
And they need a lot of maintenance to give accurate readings. The dirtier they get the higher the ORP they report.

Scott.h · Jun 27, 2017

I see no use for mine. The number is inconsistent, its always about the same. The graph goes the opposite direction of my ph, and I've found no real explanation. It jumps around out of nowhere for no apparent reason. And it can't be calibrated. So...

Daniel@R2R · Jun 27, 2017

Ok. So you guys have convinced me...anybody want my useless ORP probe?

evolved · Jun 27, 2017

Scott.h said:
The graph goes the opposite direction of my ph, and I've found no real explanation.

https://www.reef2reef.com/threads/ph-and-orp.302887/#post-3708252

Scott.h said:
And it can't be calibrated.

Yes it can.

Scott.h · Jun 27, 2017

evolved said:
https://www.reef2reef.com/threads/ph-and-orp.302887/#post-3708252

Yes it can.

Well I assumed there was a way but was referring more to this:

The tank that I have an orp probe in ran cycling for 2 months before I added the apex. Its over filtered and under stocked. I've never had any issues with that set up period. I've seen number consistently in the low 400's, and numbers in the high 200's. I have no clue other then I don't have problems. It's an ulns,not by purpose also. Ever since Triton was introduced this is the nonsense that goes on. Why?

dragon99 · Jun 27, 2017

It's fun to watch, but yeah, not really important unless ozone is being applied.

If I switch to a CaRX, I'll drop my ORP probe and never look back.

Scott.h · Jun 27, 2017

From what I understand, for those using orp you want that number to be around 400. So if the higher the number the dirtier the water how can you tell what is orp and what is dirty water?

Breadman03 · Jun 28, 2017

Scott.h said:
Well I assumed there was a way but was referring more to this:

The tank that I have an orp probe in ran cycling for 2 months before I added the apex. Its over filtered and under stocked. I've never had any issues with that set up period. I've seen number consistently in the low 400's, and numbers in the high 200's. I have no clue other then I don't have problems. It's an ulns,not by purpose also. Ever since Triton was introduced this is the nonsense that goes on. Why?

Your ORP dips appear to match with a heater cycling on. I bet it's just electrical interference that some wire rerouting would correct.

tdunmore2 · Jul 11, 2017

I don't think any probe is useless. As others have said, the ORP value is one of many indications of the health of your tank. If the PH goes up, ORP goes down, if the temperature goes up ORP likely goes down (mostly based on the drop in pH level). When you turn off your return, the ORP level probably drops. It will also drop when you add most chemicals that interact directly with the water parameters. For me, its an amazing LONG TERM indicator of tank health. If there is a big drop in ORP, and you didn't do anything to your tank, there is likely an issue. I personally don't get caught up in what the number is, as long as the number is consistent with pH/temp fluctuations and when it does change I can relate it to what I did to the tank to cause it.

Matter of fact, about 2 months ago my return pump bit the dust and the only way I knew something was wrong was because the ORP dropped very fast and the temp increased quickly.

MIReefer78 · Jul 11, 2017

So you can hook an extra PH probe into the ORP probe port? I thought the ports were probe specific

Scott.h · Jul 11, 2017

tdunmore2 said:
I don't think any probe is useless. As others have said, the ORP value is one of many indications of the health of your tank. If the PH goes up, ORP goes down, if the temperature goes up ORP likely goes down (mostly based on the drop in pH level). When you turn off your return, the ORP level probably drops. It will also drop when you add most chemicals that interact directly with the water parameters. For me, its an amazing LONG TERM indicator of tank health. If there is a big drop in ORP, and you didn't do anything to your tank, there is likely an issue. I personally don't get caught up in what the number is, as long as the number is consistent with pH/temp fluctuations and when it does change I can relate it to what I did to the tank to cause it.

Matter of fact, about 2 months ago my return pump bit the dust and the only way I knew something was wrong was because the ORP dropped very fast and the temp increased quickly.

You should set a return pump watt draw alarm both to the high end watt and also to the low end.

wmo168 · Jul 13, 2017

ORP up, your tank is good,... make sure it is around 400ish...

ksfulk · Jul 13, 2017

MIReefer78 said:
So you can hook an extra PH probe into the ORP probe port? I thought the ports were probe specific

You can change the ORP port to a pH port in the settings or classic dashboard.

tdunmore2 · Jul 13, 2017

Scott.h said:
You should set a return pump watt draw alarm both to the high end watt and also to the low end.

Agreed! I don't have the ability to measure per outlet amp draw on the classic Apex and EB8 setup I have.

Waterjockey · Jul 22, 2017

I use an orp probe, but I control my ozone addition with it. You can calibrate it, but you need to mix (saturate) the pH buffer solution with quinhydrone powder for the Apex.

ReefRondo · Jan 21, 2020

I’ve only had my apex since Xmas (Older UK style as we don’t have the new one yet...looks unlikely we will either) and my orp this morning got up and over 450.