Reading ORP ( non-expert level : )

[Shawn_epicurious]

So, yeah... I have an ORP probe in my sump. A lot of us do. I have read Randy’s article on ORP (a couple of times) ...big ole war goin on my tank right night. : )

I can’t help but watch my ORP levels... it came with my stuff; right? Randy even recommends “not to monitor it.”

Are there some general rules about what it is telling me? What does it mean if it is high? What does it mean if it is low? Why does it seem to follow my water change schedule? ...when it’s not supposed too? I can post a dozen pics like the one below... I am due for a water change tomorrow.

 

[jccaclimber]

The general rule is to listen to Randy and ignore it, I’m not kidding.
If you do notice a sudden change (that wasn’t due to the introduction of food, trace, killing algae with H2O2, or something else) then it’s a good time to walk by your tank to see what’s up, or at least make sure nothing looks off. I’ve yet to have this happen BTW.

I’ve seen great SPS tanks where it runs around 200, I’ve seen great ones where it runs around 400. I’ve seen plenty in between.

 

[Shawn_epicurious]

The general rule is to listen to Randy and ignore it, I’m not kidding.
If you do notice a sudden change (that wasn’t due to the introduction of food, trace, killing algae with H2O2, or something else) then it’s a good time to walk by your tank to see what’s up, or at least make sure nothing looks off. I’ve yet to have this happen BTW.

I’ve seen great SPS tanks where it runs around 200, I’ve seen great ones where it runs around 400. I’ve seen plenty in between.

I love this response by the way! It is impossible to ignore lol. I see the number move everytime I look at my fusion app. I am seriously considering just unplugging that probe. : )

 

[taricha]

the daily cycle is pH driven (I think). Water changes or feeding could bring many reducing or oxidizing substances (more likely reducing). Randy has some good graphs on feeding dropping his ORP.

 

[Ippyroy]

There are some things that ORP is good for. Randy goes over it in mastering your Apex for powerheads. Mine was in the low 200s originally and 6 months later it has creeped up to the high 300s. I personally don't worry about it unless there is a quick and drastic change, similar to the salt probe. Both of these are rather unimportant probes, but both can warn you about a major problem before it crashes your system.

 

[MnFish1]

So, yeah... I have an ORP probe in my sump. A lot of us do. I have read Randy’s article on ORP (a couple of times) ...big ole war goin on my tank right night. : )

I can’t help but watch my ORP levels... it came with my stuff; right? Randy even recommends “not to monitor it.”

Are there some general rules about what it is telling me? What does it mean if it is high? What does it mean if it is low? Why does it seem to follow my water change schedule? ...when it’s not supposed too? I can post a dozen pics like the one below... I am due for a water change tomorrow.

If you look - at your pH graph - you will probably see that the swings in ORP reflect changes (in the opposite direction) of your pH (at least I think this is the relationship - I stopped monitoring it a long time ago) - Now - lets say your ORP is always 350-450 on a daily basis and all the sudden its 100 (unlikely) - I would look for something dead in the tank - or a filter problem etc - for minute by minute monitoring - probably not that helpful. Hope this helps

 

[Reef man 89]

Mines at a 470 right now after a big water change yesterday. I have read randy saying many times in many different threads not to worry about it. It’s good only if your running ozone.

 

[Shawn_epicurious]

If you look - at your pH graph - you will probably see that the swings in ORP reflect changes (in the opposite direction) of your pH (at least I think this is the relationship - I stopped monitoring it a long time ago) - Now - lets say your ORP is always 350-450 on a daily basis and all the sudden its 100 (unlikely) - I would look for something dead in the tank - or a filter problem etc - for minute by minute monitoring - probably not that helpful. Hope this helps

I have never noticed that before! This does help (and yeah, that’s all I use it for... spikes or dips)

 

[Ippyroy]

ORP by itself is not important. But huge swings can tell you multiple things. It will dip very low if you over dose Alk or if your sandbed got disturbed by something like a fallen powerhead. A very helpful and useless number all at the same time. Once it has settled you can set alarms for it that will help you prevent a catastrophe.

 

[BackToTheReef]

Mines at a 470 right now after a big water change yesterday. I have read randy saying many times in many different threads not to worry about it. It’s good only if your running ozone.

I thought I just read/heard that since GAC affects ORP montioring ORP can be a way to tell when to swap your GAC.

 

[Reef man 89]

I thought I just read/heard that since GAC affects ORP montioring ORP can be a way to tell when to swap your GAC.

I’m not sure I just going off what I have seen randy say on many threads asking the say question. @Randy Holmes-Farley

 

[Wolf89]

does anyone know why my orp is 650? I am dosing lanthanum daily, is that why? is 650 a problem?

 

[taricha]

does anyone know why my orp is 650? I am dosing lanthanum daily, is that why? is 650 a problem?

" In other situations, such as the purification of tap water for drinking, allowing the oxidizers to win is fine. A high enough ORP (650+ mv) can kill most bacteria in a few seconds." -Randy's Article

I think it's a faulty measurement or you've created a very toxic environment. You should be able to look at the tank and tell which it is.

 

[MnFish1]

does anyone know why my orp is 650? I am dosing lanthanum daily, is that why? is 650 a problem?

Did it just 'spike up' - it could be (likely is) - a faulty probe (or calibration issue) unless you are dosing (overdosing) Ozone, etc? Otherwise, a high ORP is considered a non-issue unless you are dosing oxidizers.

 

[Wolf89]

Did it just 'spike up' - it could be (likely is) - a faulty probe (or calibration issue) unless you are dosing (overdosing) Ozone, etc? Otherwise, a high ORP is considered a non-issue unless you are dosing oxidizers.

Its been saying that for several weeks. I missed a lanthanum dose last night and now it is low 500s. I really think that may be causing faulty readings

 

[Wolf89]

Did it just 'spike up' - it could be (likely is) - a faulty probe (or calibration issue) unless you are dosing (overdosing) Ozone, etc? Otherwise, a high ORP is considered a non-issue unless you are dosing oxidizers.

But yes, I am using an ozone generator and controller. It is only supposed to come on around 350 ORP, so I don't yhink its that. The controller also let's you know when the generator is on, and it hasnt been on for the past few times I've looked. Plus, this is a 50mg/hour unit, which is apparently underpowered for my 220 gallon system

 

[MnFish1]

But yes, I am using an ozone generator and controller. It is only supposed to come on around 350 ORP, so I don't yhink its that. The controller also let's you know when the generator is on, and it hasnt been on for the past few times I've looked. Plus, this is a 50mg/hour unit, which is apparently underpowered for my 220 gallon system

I would 'make sure' that there isnt a glitch with your controller - I had an apex one time that said everything was off - when in fact it was 'on' - but if your ORP was really 650 everything in your tank would look bad. Its not the 'absolute number' to watch anyway - its changes from day to day. Sometimes cleaning the probe helps - sometimes is a bubble or algae on the probe, etc etc - that causes it to seem artificially high'