A couple of ORP questions??

[Brutuscz]

I recently purchased an ORP meter. This is a handheld model, not very expensive. Of course, I forgot to purchase calibration solution. So, I just used it out of the box. The numbers I measured so far:
distilled water 380
tap water 375
quarantine pool with no fish 335
pool1 with fish 320
pool2 with fish 325
my pond 315
my reef tank 90gal 285

Do these numbers sound reasonable? I will orders some calibration solution, just wondered if I was in the ballpark. I read orp is not very useful in a saltwater tank..only to help if ozone is being utilized. Does this sound correct? Thanks for any advice.

[JasPR]

No. Because ORP is not a measurement like temperature. It is relative to pH and oxygen levels. So in ponds we use it to monitor change, specifically, a trend in the wrong direction.
Your reef tank has a pH in the mid 8 range. Your koi pond is likely more in the 7.5 range? The temperature reading will effect potential oxygen levels and this is the most important influence on ORP in a living system.
This would also mean that the same reading in both settings ( pond and aquarium) is possible but it would mean very different things. JR

[MCA]

if your tap water from a public source ..is not reading >600mV.....you are not getting sterile safe drinking water. If you are running tap through through some type of filter first to remove chlorine/chloramine...you may be reading less than 600mV. From the reading you reported...I can only guess you are filtering out chlorine/chloramine.

[cmungo]

All the reading are a little close to each other for me. I would wait on the calibration fluid and see what is happening.

[Brutuscz]

Quote: Originally Posted by MCA if your tap water from a public source ..is not reading >600mV.....you are not getting sterile safe drinking water. If you are running tap through through some type of filter first to remove chlorine/chloramine...you may be reading less than 600mV. From the reading you reported...I can only guess you are filtering out chlorine/chloramine.

No, that was straight from the tap. The water here is very soft. My tds is 50 with GH-40-60 and KH-20-30. That is straight from the faucet. I have already had a ph crash in one of my quarantine tanks this season. I learned my lesson. I add baking soda regularly. It hasn't happened again. I would like to add oyster shells, but don't know where to get them. Any ideas?

[mstrseed]

Quote: Originally Posted by Brutuscz No, that was straight from the tap. The water here is very soft. My tds is 50 with GH-40-60 and KH-20-30. That is straight from the faucet. I have already had a ph crash in one of my quarantine tanks this season. I learned my lesson. I add baking soda regularly. It hasn't happened again. I would like to add oyster shells, but don't know where to get them. Any ideas?

Sea food restaurant..................................

[RookieKoiGuy]

Quote: Originally Posted by Brutuscz No, that was straight from the tap. The water here is very soft. My tds is 50 with GH-40-60 and KH-20-30. That is straight from the faucet. I have already had a ph crash in one of my quarantine tanks this season. I learned my lesson. I add baking soda regularly. It hasn't happened again. I would like to add oyster shells, but don't know where to get them. Any ideas?

Sushi Bar

[Sangreaal]

Quote: Originally Posted by Brutuscz No, that was straight from the tap. The water here is very soft. My tds is 50 with GH-40-60 and KH-20-30. That is straight from the faucet. I have already had a ph crash in one of my quarantine tanks this season. I learned my lesson. I add baking soda regularly. It hasn't happened again. I would like to add oyster shells, but don't know where to get them. Any ideas?

City boys....
Feed store, chicken dept. You can buy it by the 50lb sack....

[JasPR]

If you want to understand ORP do not read the internet!

ORP is a measurement of a net reaction or redux potential of any fluid. In this regard you will always read that there is a relationship between PH and ORP. That can't be denied. But this is the slippery slope that leads the new tester to see ORP readings as a measurement of a number that is either good or bad.
Several years ago I created a pond index value chart that showed in some ponds with a certain temperatures, oxygen levels and pH that a reading of 300 mV was excellent. And that in other ponds, a reading of 380mv was really needed to be the 'same' as the the 300 mV in the first pond.

In other words, the ORP reading is meaningless without the context of the temperature, pH and oxygen level the pond exhibits. This is because, in our case as pond keepers, we need to see a highly oxidative state in the presence of the correct parameters for life in the pond.
Out another way, if you wanted a cosmetic higher ORP number, all one needs to do is change the pH. Or add chlorine or PP to the water. That obviously is not the point of the exercise.

So taking readings from multiple sources and trying to make a commentary about one against the other is to not understand why we use ORP in living systems to begin with. JR

[MCA]

Totally agree with what JR said. I issue is that public water that uses chlorine or chloramine to your house should be reading in the 600mV range to be sterile water according to World Health Organization. If the water is indeed down in the sub 400mV range....not sterile. We want sterile drinking water....but indeed NOT sterile pond water.

Also you can use the right combination of filtration and aeration to get your pond in the >300mV range without the use of oxidizers such as PP, O3,...etc. Plain old aeration worls wonders!!!


KOI NATIONS


[FONT='Arial','sans-serif']Introduction[/font]

[FONT='Arial','sans-serif']No, I am not talking about an Optional Retirement Program. That is an “ORP” you might find discussed in AARP’s magazine. We are discussing Oxidation Reduction Potential. Boy, that was a mouthful. What is it? Do I have to be a rocket scientist to understand it? Is it anything of real interest for the average nishikigoi keeper? No, you do NOT have to be rocket scientist to have a working knowledge of ORP for our hobby. ORP as one more tool you can use to care for your Living Jewels.[/font]
[FONT='Arial','sans-serif']What is ORP?[/font]

[FONT='Arial','sans-serif']ORP is one more those three letter acronyms (TLAs) you get to learn when you read books and magazines about nishikigoi keeping. Simply put, ORP is an indication of how free the water is from organic pollution. In general, cleaner, less polluted, water is better for our nishikigoi. Cleaner water means our nishikigoi can spend their energy on growth and skin quality. They will not have to spend energy trying to overcome poor water conditions.[/font]
[FONT='Arial','sans-serif']Oxidation and reduction were originally thought of as the adding or removing oxygen from another material. This is like adding oxygen to iron to create rust. Now oxidation and reduction are thought of more in terms of the ability to steal an electron (oxidation), or to give up an electron (reduction). [/font]
How ORP is Measured

[FONT='Arial','sans-serif']OK, so how do we measure ORP? ORP is about the ability to move electrons. Therefore an ORP meter uses a special probe in the water to measure the potential for moving electrons in the water. This potential is displayed by the ORP meter in millivolts. [/font]
[FONT='Arial','sans-serif']Personally I use an ORP meter that I can calibrate. I follow the manufacturer’s instructions on how to clean the probe and calibrate the meter. I definitely clean and recalibrate before any chemical treatment such as the use of potassium permanganate. I want to know the impact of the dose, not just the theoretical calculated impact. Neither the nishikigoi nor I like surprises when it comes to pond chemistry.[/font]
[FONT='Arial','sans-serif']ORP Levels

[FONT='Arial','sans-serif']Can ORP be too high in a pond? Can the water be too clean? Simple answer…yep. Water can indeed be too clean or oxidative for our fish. In our pond we are NOT trying to create sterile water. Sterile water means no filter bacteria, no algae, and no fish. Bad karma. Bad joss. No thanks.[/font]
[/font]· [FONT='Arial','sans-serif']Here are some ORP ranges you might see in a nishikigoi pond and what they can indicate: [/font]
· [FONT='Arial','sans-serif']<120mv[/font][FONT='Arial','sans-serif']: The water is very polluted. The pond filtration and aeration has not kept up with the organic load.[/font]
· [FONT='Arial','sans-serif']120-200mv[/font][FONT='Arial','sans-serif']: The water is polluted. The pond filtration and aeration is struggling to keep up with the organic load.[/font]
· [FONT='Arial','sans-serif']200-300mv[/font][FONT='Arial','sans-serif']: The water is relative clean. The pond filtration and aeration are keeping up with the organic load.[/font]
· [FONT='Arial','sans-serif']300-400mv[/font][FONT='Arial','sans-serif']: The water is extremely clean. The pond filtration and aeration are more than keeping up with the load. This should be the target range for all nishikigoi ponds.[/font]
· [FONT='Arial','sans-serif']400-500mv[/font][FONT='Arial','sans-serif']: This range may be too oxidative for long range good nishikigoi health. May indicate presence of a chemical oxidizer such as potassium permanganate, chlorine, or ozone.[/font]
[FONT='Arial','sans-serif']· [FONT='Arial','sans-serif']500-550mv[/font][FONT='Arial','sans-serif']: Very oxidative water suitable for killing parasites. Exposure should not be longer than 8 hours.[/font]
· [FONT='Arial','sans-serif']550-650mv[/font][FONT='Arial','sans-serif']: Too oxidative for nishikigoi long term or short term.[/font]
· [FONT='Arial','sans-serif']650-700mv[/font][FONT='Arial','sans-serif']: In this range bacteria are killed within a few seconds and the water is considered sterile enough to be potable. [/font]
Items that Impact ORP Readings

[FONT='Arial','sans-serif']There are several factors that will change the ORP level of the pond water. [/font]
· [FONT='Arial','sans-serif']Organic Load[/font][FONT='Arial','sans-serif']: The most obvious thing that will change the ORP readings is the absence or presence of organic pollution. After all, for most of us hobbyists, this is one of the key reasons we purchased and use an ORP meter.[/font]
· [FONT='Arial','sans-serif']Dissolved Oxygen[/font][FONT='Arial','sans-serif']: Remember how we said that originally ORP was thought of as the adding or removing or oxygen to another substance. If we increase the dissolved oxygen levels in the pond, the ORP values will go up. This is one of the reasons folks always hear me preaching for more aeration. [/font]
· [FONT='Arial','sans-serif']pH[/font][FONT='Arial','sans-serif']: ORP moves inversely with pH changes. If the pH drops, the ORP levels go up. Bring up the pH, the ORP levels decrease. For example, if your pond ORP is 400mv or higher and there is no oxidizing chemical present, double check the water pH. The pH might be lower than you think it is and lower than you want it to be.[/font]
· [FONT='Arial','sans-serif']Calibrated Meter[/font][FONT='Arial','sans-serif']: Sounds like a no-brainer. You need a meter that has been calibrated and has good batteries, or an AC adapter. A inaccurate meter might be more dangerous than no meter at all if you are using the meter readings to dose oxidizing chemicals.[/font]
[FONT='Arial','sans-serif']Using ORP[/font]

[FONT='Arial','sans-serif']There are many practical uses of ORP for the average nishikigoi hobbyists.[/font]
· [FONT='Arial','sans-serif']Checking Filtration[/font][FONT='Arial','sans-serif']: Measure the ORP of a stable pond system. This will tell you how well the pond’s filtration and aeration are handling the load. Expand the filtration and aeration as needed. You can monitor the ORP over time to see if there is any indication that with a growing load (i.e., larger fish, more fish) the pond system is nearing its current limits.[/font]
· [FONT='Arial','sans-serif']Measuring Pond Treatments[/font][FONT='Arial','sans-serif']: You can ORP reading to help you perform a pond treatment for parasites with an oxidizer such potassium permanganate. Slowly add the chemical and constantly monitor the ORP levels using a calibrated meter. Bring the ORP level to the target level for the target duration. [/font]
· [FONT='Arial','sans-serif']Checking Dechlorination[/font][FONT='Arial','sans-serif']: Chlorine is one of the most potent oxidizer chemicals available. That is why it is used by government agencies to provide potable water to your home. As koi keeper we do not want the chlorinated water (ORP typically around 650mv) to drive up the pond’s ORP. We can use the ORP readings to add enough dechlorinating chemical, such as sodium thiosulphate, to just offset the impact of the chlorine. Ideally, when all the new water has been added, the ORP is the same, or only slightly higher, than before the new water was added.[/font]
[FONT='Arial','sans-serif']Summary[/font]

[FONT='Arial','sans-serif']ORP readings give you a snapshot of the pollution levels in the pond system. ORP is measured in millivolts using an ORP meter. ORP readings can help you decide if the filtration and aeration should be expanded or the load should be reduced. The readings can also help you more accurately use oxidizing chemicals for parasite treatments. ORP is simply one more tool you can use to better plan and maintain the home of your Living Jewels.[/font]
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