Very low ORP

[Centerline]

A couple of months ago my ORP levels dropped to 160-170 and have stayed there. At first I thought it was due to the addition of a new live rock structure (fully cured and cycled branch) that I had assembled out of several smaller bits with West System epoxy. I let the epoxy cure for a couple of weeks in the sun and then the whole thing cycle for a couple of more weeks. After adding the rock I experienced no new tank cycle or other irregularities that were noticeable. Within 3 weeks of adding the new rock ORP had dropped to 160-170 and as stated above, stayed there. Visually the tank was still doing fine, growth, polyp extension, general health seemed fine BUT over the last couple of weeks growth appears to have stopped across the board. I am aware there are many potential reasons for this but it seems relevant to diagnosis.

Some of the steps I have taken to diagnose the issue.

• Replaced the ORP probe. No change.
• Tested the new and old ORP probe with 400Mv solution. Results - 400Mv.
• Moved from biweekly 10% water changes to weekly 10% water changes. No change.

About the tank.

SPS
80 gl - a few years old
shallow sand bed
skimmer
crazy flow
cal 450 / alk 11-12 / mg 1400
po4 .0 / N .5 - 1
ph 7.7- 8.2 daily swing (may have 02 issues in house)


Additives
Red Sea Pro Salt @ 35 ppt
Prodibio bacteria supplement @ 2 x monthly
N0P0x daily (1/2 recommended dosage)
Reef Energy A/B daily
RedSea Colors weekly (based on cal depletion)
N&P as needed

Thank you for taking the time to read this and any advice would be well received.

 

[Randy Holmes-Farley]

I'n not sure the ORP is related to the growth stoppage. In general, I do not consider ORP worth worrying about.

What corals stopped growing? Are you monitoring nutrients?

 

[Centerline]

I'n not sure the ORP is related to the growth stoppage. In general, I do not consider ORP worth worrying about.

What corals stopped growing? Are you monitoring nutrients?

Nutrients look pretty good, maybe a little light on N. Monties and sps growth have slowed right down though of course it could be related to anything. So would you recommend just ignoring that low orp number and pressing on? If so I'm going to have to remove that orp probe because its making me crazy .

 

[skim]

Your ORP will drop and stay there with all the additives. You may want to stop one or two of them and see what kind of response you get. I would stop the NoPox as you are using Prodibio and maybe cut back the Reef Energy A/B to once or twice a week. You don't mention the use of any GAC you want to add some to the system, maybe something has released some toxin that has caused this response. Just remember Prodibio is Bacteria and some of them require O2 and as O2 drops so will your ORP. I think you just maybe adding too much stuff and now it may have reached a level where it is bothering the Corals. I would add some Carbon and stop the Additives for a few days and see what happens can always add but usually hard to remove.

 

[Centerline]

Your ORP will drop and stay there with all the additives. You may want to stop one or two of them and see what kind of response you get. I would stop the NoPox as you are using Prodibio and maybe cut back the Reef Energy A/B to once or twice a week. You don't mention the use of any GAC you want to add some to the system, maybe something has released some toxin that has caused this response. Just remember Prodibio is Bacteria and some of them require O2 and as O2 drops so will your ORP. I think you just maybe adding too much stuff and now it may have reached a level where it is bothering the Corals. I would add some Carbon and stop the Additives for a few days and see what happens can always add but usually hard to remove.

Yup, I had wondered if the bacterial populations were getting out of hand and gobbling all the 02 up. NoPox is pretty potent food stuff and has a remarkable ability to help lower excess n/p. I have been using vodka and prodiobio for few years with great results but it may be the bacteria are responding a little too well with NoPox. GAC seems like a good idea as well. I don't ever run it as my tank is always crystal clear. Thanks for putting some thought into this!

 

[Randy Holmes-Farley]

So would you recommend just ignoring that low orp number and pressing on? If so I'm going to have to remove that orp probe because its making me crazy .

Yes.

 

[skim]

Yes sorry, I forgot to say I also agree with not putting too much into ORP readings as so many things affect the readings, unless you are running Ozone, but that is a whole nother beast.

 

[Engloid]

After reading articles, I have began to not put much into the ORP readings, but I do watch it since it's on the dashboard. I notice that after I add Seachem Fuel, it drops pretty badly. Corals seem to be fine though, so I'm not worrying about it. The thing I don't understand is why The Neptune Apex comes with a probe that's apparently not really monitoring something worth monitoring. I wonder what their logic is in including it in the package instead of a different probe or possibly cost savings.

 

[skim]

I would assume they add that so if you decided to run Ozone you would be able to control it. It does not mean that it can't be useful as you have see for yourself, you do something in the tank ORP drops, you add food Orp drops, you add an additive, Orp drops, so you get an idea of what happens and when. Now say you come home from work and you have or anyone else has done anything to the tank and the ORP is low, not just randomly low but low for no reason, then you may want to take a close look around and count fish and snails or shrimp as something may have died. ORP reacts quickly to changes and when something dies it starts to decompose within minutes, which will use O2 and as O2 drops so will your ORP. So long story short it can be a quick alert to trouble brewing.

 

[Randy Holmes-Farley]

After reading articles, I have began to not put much into the ORP readings, but I do watch it since it's on the dashboard. I notice that after I add Seachem Fuel, it drops pretty badly. Corals seem to be fine though, so I'm not worrying about it. The thing I don't understand is why The Neptune Apex comes with a probe that's apparently not really monitoring something worth monitoring. I wonder what their logic is in including it in the package instead of a different probe or possibly cost savings.

There aren't many useful probes, and if you are using ozone, the ORP is useful to make sure you do not overdo it.

 

[Centerline]

And here it is a couple of months later and ORP is still in the 160-170 range. SPS, chalice, etc all growing fine. So, I'm calling BS on ORP as an indicator that my tank sucks. As to why it dropped so much and stayed there I'm guessing that the bacterial load is pretty high and gobbling O2. I can raise N to 10 and P to .05 and 24 hours later N is at 1 and P is at .01 so... the ORP probe is GONE. Sitting in a box with other lonely and discarded reef keeping gear. That dam thing was absolutely making me crazy.

I would like an O2 probe though .... just kidding, maybe.

 

[Randy Holmes-Farley]

Sounds good.

Happy Reefing.

 

[Engloid]

I'm new to having any controller at all, so excuse the fact that things aren't perfect yet. I'm working on it.
My salinity needs calibration, and I am slowly ramping up salinity to where I want it, as the chart shows. It's only been set up about a week and I found that calibrating a new probe didn't seem to work right. The LFS said the Neptune representative even told them it's best to leave them in the sump a week or two before calibrating them. Therefore, ignore the specific numbers, but the pattern I see is interesting.

I am doing NOTHING to control or change ORP intentionally....but I do watch it just to see what it does, out of curiosity. On the ORP, the dips seem to often be associated with feeding times or dosing of Seachem Fuel. Aside from those dips, it seems that as the salinity increases, so does the peaks of the ORP.

 

[Randy Holmes-Farley]

I am doing NOTHING to control or change ORP intentionally....but I do watch it just to see what it does, out of curiosity.

And you shouldn't. IMO, ORP is not a number that should be intentionally altered since it is never clear that such a change is actually beneficial to tank organisms.

The changes are msot likely reflecting the relative proportions fo the forms of trace elements such as iron and manganese in more oxidized vs more reduced forms. For example, the relative amounts of ferrous (Fe++) iron and ferric (Fe+++) iron.

 

[ClownSchool]

After reading articles, I have began to not put much into the ORP readings, but I do watch it since it's on the dashboard. I notice that after I add Seachem Fuel, it drops pretty badly. Corals seem to be fine though, so I'm not worrying about it. The thing I don't understand is why The Neptune Apex comes with a probe that's apparently not really monitoring something worth monitoring. I wonder what their logic is in including it in the package instead of a different probe or possibly cost savings.

Yeah, I’d much rather have a salinity probe included than the ORP.

 

[Andrew Schubert]

I've been running Ozone Generator through the Avast Mutiny Reactor for 4 months now. I'm using dryer beads to dry the air; and yet running the ozone generator 24//7 at the highest setting (daily at "10"), The highest my ORP ever gets is 270. During the day, it will fall to 240. Does this seem right to anyone? I'm honestly wondering if my ozone generator is faulty; although, when I remove the hose I can smell the ozone coming from the tubbing. Thoughts or suggestions? My water clarity does look decent however...so not sure what to make of this.

 

[Randy Holmes-Farley]

I've been running Ozone Generator through the Avast Mutiny Reactor for 4 months now. I'm using dryer beads to dry the air; and yet running the ozone generator 24//7 at the highest setting (daily at "10"), The highest my ORP ever gets is 270. During the day, it will fall to 240. Does this seem right to anyone? I'm honestly wondering if my ozone generator is faulty; although, when I remove the hose I can smell the ozone coming from the tubbing. Thoughts or suggestions? My water clarity does look decent however...so not sure what to make of this.

I expect it is operating fine, and the ORP may just read lower than many tanks because the ORP measurement is not accurate.

That said, it may be accurate and you tank just runs low on ORP, which is neither good nor bad, IMO.

FWIW, lower during the day when pH is higher is expected.

 

[Jay Pros]

I just setup an ozone generator on my tank. I have it running from 11:30pm through 3:30am. As soon as the ozone generator comes on, my orp drops then it comes back up around the time the generator goes. What could be possibly driving this?