My ORP Hurts

[Anonymous]

Cannot seem to get my ORP above 300, hovers around 280.....bugs the hell outta me but not sure if this is really a problem.

My parameters are spot on, 0/0/<10 and have been for months. pH 8.2, temp 79. Nothing dying or dead, corals thriving. This particular reef is a 200 gal, up 5 months, so some rock still not mature. Pretty good bioload. ETS 1000 running 24/7, normal output of skimmate. Water changes 30% every month with RO/DI.

Is an ORP of 400 really expected in a somewhat immature tank (less than a year)? Anything to be concerned about? Specifically, what keeps ORP down? Feed cryopaste 3-4X weekly...have you guys that do this noticed your ORP drop?

thanks.

elvis

 

[Anonymous]

I am not sure why your ORP would be low like that. I am not trying to brag (bad karma), but just for comparison I have a six week old 180 gallon with 220# of Marshal Islands live rock with an ETS 800 skimmer that I run for only about 12 hours a day (night actually). My ORP is now 450mV, if you can believe that. I even wrote Bob Fenner about the high ORP w/o ozone and he said it's ok. I thought it might be my probe so I checked it with a different meter.

I was told that phytoplankton can give you a falsely low ORP reading. Maybe the stuff that you are using has a similar effect. It all has to do with electrical conductivity, as I understand. I am no expert, but from what you describe you seem to be on track. Your skimmer should be rockin' and rollin' on that size of tank. How much protein is it pulling out? Since you say that your corals are thriving, perhaps it's just your monitor or the additives that are messed up. Try using a toothbrush to clean your ORP probe - that's what I do from time to time. The most important thing is that your livestock is doing well, so maybe it's just your reading that is off, not your tank. I hope so.

 

[Anonymous]

Jim,
Thanks for the reply.
Clean my probe regularly but this just drops the reading more. Just cleaned it again.
ORP dropped to 245. This reading should be associated with bad stuff but nothing wrong whatsoever, as far as I can tell.

I am beginning to think I have a bad probe.

go figure.


elvis

 

[Anonymous]

Elvis,

When you consider that freshly mixed saltwater has an ORP of 280-300 mV, I'd say you are doing pretty good. My ORP is in the same area as yours. When it starts to read above 320, I know it's time to clean my probe.

Jim-san,

Have you calibrated your probe lately? A non-O3 ORP of 450 is highly suspect unless you are using some other oxidant.

------------------
Regards - John

 

[Anonymous]

I just wrote Bob Fenner with that EXACT question and he said that it is possible. To be honest, I care more about the health of the corals than I do about the ORP number. BF suggested that the CA reactor may be responsible for my high readings. As I said, I checked it with two different meter/probe combos. I am not going to worry about it too much.

 

[Anonymous]

Hmmmm....

Well.. ever since I bought my Aquacontroller, I've had my ORP at above 450 all the time. That's when I first got it. After that, I've added live rocks... corals... and now, the level is keeping pretty steady around 500.

Also looking at the little instruction booklet that came with the controller, I kinda got the impression that higher ORP is better? *shrugs*

 

[Anonymous]

Personally, I would not put any emphasis on ORP numbers. Too many things impact ORP and ORP measurement to make it particularly useful.

I haven't measured it in my tank since my probe was accidently destroyed several years ago.

------------------
Randy Holmes-Farley

 

[Anonymous]

Elvis,

How do the animals look?

------------------
Dan
Minotaur15 on #reefs
http://www.tcnj.edu/~maughme2/

 

[Anonymous]

John,

I don't follow you, I've never seen my make up water have a orp of 280. Its more like 220 or a little lower. I airate it for two day plus run a large pump for movement.

I think in Elvisdoc's case this is to a norm for him. With him feeding his filter feeders 4x a week and other inputs of organics; its only normal to have a lower reading.

I have another one for ya though; when I put a new over flow on and increase my turnover by 5x. My orp droped by about 30 and never went back up. But whats important is my animals responded well and my skimmer pulled more out.

If it works don't fix it.

Bill

 

[Anonymous]

I have a heavy population of corals and also feed heavily, and the ORP reading I see is usually around 430 these days. I wouldn't sweat it either.

 

[Anonymous]

I agree with you guys. I was just trying to tell Elvis that he has nothing to worry about.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote

I've never seen my make up water have a orp of 280. Its more like 220 or a little lower. I airate it for two day plus run a large pump for movement.

Are you using RO/DI water? Do you use any water conditioners such as Amquel? As has been said, a lot of things can affect the ORP reading. IMHO, anything above 350 without using ozone or some other oxidant makes me think the reading is wrong.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote

I think in Elvisdoc's case this is to a norm for him. With him feeding his filter feeders 4x a week and other inputs of organics; its only normal to have a lower reading.

I agree and I have the same values with a similar feeding routine in a heavily stocked tank.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote

I have another one for ya though; when I put a new over flow on and increase my turnover by 5x. My orp droped by about 30 and never went back up. But whats important is my animals responded well and my skimmer pulled more out.

You got me but a 30 mV change is not to big a swing.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote

If it works don't fix it.

Agreed.


------------------
Regards - John

 

[Anonymous]

I had ORP probe problems a few weeks ago. Started a thread here about it. These are the things I learned from American Marine (the makers of Pinpoint probes):

1) There is no such thing as a reference liquid. There is no "right" measure for fresh seawater, or distilled water, or anything else. The only useful thing you can do to check the validity of your readings is to use a second device and see if they are wildly apart.

2) Measuring ORP is a somewhat imprecise measure of what's going on in your water. The exact number is much less important than the trend in the number over time. Watch for unusual dips, etc. This is backed up by most of the major reef authors.

3) Cleaning your ORP probe will drop your reading because you are removing algae growing on the tip. As this algae photosynthesizes, it releases O2 at the tip which gives an artificially higher reading.

4) According to American Marine, any reading at 280mV or higher is probably a "legit" reading.

5) My readings were very low (around 180) for weeks, until I shorted the two probe leads to each other, thus draining any accumulated charge. This required bridging the central lead on the coax to the outer wrap lead for about 10-15 seconds. This was done at American Marine's suggestion. Then my readings started climbing slowly over the next two weeks until now they hover around 380mV most of the time.

6) Depending upon the author, readings above 400mV or above 500vM are detrimental to your tank's inhabitants.

FWIW,

-Jim

[This message has been edited by chapman_jim (edited 18 February 2000).]

[This message has been edited by chapman_jim (edited 18 February 2000).]

 

[Anonymous]

Elvis,

I thought you were running ozone on your tank? Did you stop?

------------------
Regards - John

 

[Anonymous]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by chapman_jim:
There is no such thing as a reference liquid. There is no "right" measure for fresh seawater, or distilled water, or anything else. The only useful thing you can do to check the validity of your readings is to use a second device and see if they are wildly apart.<HR></BLOCKQUOTE>

You can verify if you probe is functioning properly with quinhydrone saturated pH 4 and pH 7 calibration solutions.


------------------
Regards - John

 

[Anonymous]

Thanks for the responses, guys. Looks like a topic many others have thought about as well.
My tank looks great so not too worried. Just somewhat confusing as I had heard you guys talk about your 400 ORP's and I guess the peer pressure got to me...

I do run ozone with the Aquacontoller so the low ORP is even more confusing. That's why I asked about the ORP, as an inaccurate reading could be potentially hazardous with O3. So until I solve this little question my O3 runs with lights on only. I agree with Randy's thinking in that I doubt my ORP is way off because I think my tank inhabitants would be telling me and they are thriving. I have made a deal for some quinhydrone, have the pH 4 and 7, and will be calibrating the ORP probe. Talked with Curt at Neptune and we checked the internal settings which are correct. We shall see. If the lower ORP is the price I pay for feeding phyto, it is small indeed as the animals have really responded.

On a side note, just got a shipment from DE, Steve Tyree's coral farm, and it is awesome.
Frags started feeding within 5 minutes of acclimation. Wow. Have never seen that in MO corals before, usually take awhile to feed, IME. Packing job great, highly recommend them.

thanks again for the input,

elvis

 

[Anonymous]

Elvis,

What kind of ozone generator are you using? Could it be that it is not functioning as well as it did in the past? I know that with the UV bulb type generators the bulbs can get dirty and affect the output. The UV bulbs also need to be replaced periodically.

How about turning the ozone off and see if it has much of an effect on the ORP.

------------------
Regards - John

 

[Anonymous]

Brand new Clearwater 1200 (200mg/hr).
Good thought, tho.


elvis

 

[Anonymous]

JohnL;

I was told by both American Marine and Neptune Systems that the calibration liquids are useless, but I'm not a chemist so you might be right and they're wrong. In any case, I've seen several people mention using the Ph calibration solutions, but no one ever says how? If you stick your ORP probe into Ph 4 calibration solution, what reading are you supposed to get? What about Ph 7?

-Jim

 

[Anonymous]

Jim,

You also need quinhydrone powder. You have to add enough of it to each of the solutions so that a little bit remains undisolved.

When you put the probe in the quinhydrone saturated pH 7 solution, you should get a reading of 90 +/- 15.

When you put the probe in the quinhydrone saturated pH 4 solution, you should get a reading of 170 - 185 higher than the pH 4.

Ultra Life sells a kit with all the chemicals. I think Aquadyne and Red Sea do also.

I used to have readings of 400-450 mV until I cleaned my probe well enough to pass the test

I'm using an Ultra Life probe now that has a removable plastic tip. This allows me to clean the metal band a lot better than the neptune probe I was using did.

I clean my probe about once a week or so, my ORP is consistently between 280 and 300. When it drifts up past 310 or so, I know it it's time to clean the probe again.
--
HTH - John

 

[Anonymous]

Thanks John.
I will probably discover it is calibrated just fine already. Using the Neptune probes and clean them alot like you. Glad to hear someone else is getting these ORP numbers and everything is fine.

Will let you know.

elvis