Is ORP a meaningful parameter ? Help test the benifits.

[Automate]

OK I am about to install an online ORP probe (should be here in a week) for continuous ORP measurement. As I also have the facility to trend this data I was thinking of running some tests to understand the relationship between ORP and water quality. OH I was hoping not to stress my discus, so not doing a WC for 2 weeks is out of the question. I was thinking of seeing how aeration may effect ORP and what difference doing 2 x 20 litres WC ver 1 x40L WC change effects ORP readings over a period of time. As I can trend temperature, conductivity, pH and WC litres I should be able to see if ORP provides any useful correlation to water quality for discus..These tests would be conducted over say a 2 month period with all data logged every 15 minutes.. If you have any thoughts of some constructive tests I could make lets hear about them.

rob

[Graham]

Rob just remember that ORP is a constantly moving number,,anything that's done to the tank affects that number...feed the fish and it'll go down, add a de-chlor and it'll go down, add PP and it'll go through the roof.

If it can hang around the 350 area then you'll have good water

Keep us posted with the numbers, should be interesting

G

[kaceyo]

I'll definitly be watching this one too. Sounds interesting.

[Automate]

Got my probe installed this weekend....reading about 120 mV at the moment and went down when I did a water change...I assumed it would go up. :confused:

I haven't done a WC for a few days. I'll trend it for a couple of days prior to the next water change.

PH and ORP are at the ends and conductivity is the center electrode.

http://img.photobucket.com/albums/v319/rjconway/aquaprobes.jpg

[jack396]

Sorry guys, and ORP means?:confused:

[Graham]

Oxygen Reduction Potential or Redox...the water ability to oxidize pollutants. It's measured by an electronic meter and the reading is given in millivolts. To have good water the reading should be up in the 350Mv range.

It is not a constant number

Help ?

G

[gg5190]

Sorry guys, and ORP means?:confused:

Oxidation-Reduction Potential...

[Paul Lucas]

reading about 120 mV at the moment and went down when I did a water change...I assumed it would go up

That was the way I thought it would go but . . . . stored water which has been warming to the tank temperature for 24 hours does indeed drop in mV. Your figures seem low and perhaps you should try and inject some 03 to get it up somewhere near the 350 that Graham suggests. I've had it at 375 mV and it's been great. No adverse affects on the fish and crystal clear sweet smelling water!

Paul Lucas - Southampton UK

[kaceyo]

Do you know what the mv of straight aged (well oxigenated) tap water before adding anything is? Without additional chemical oxidation you can only try to bring tank water as close as possible to that number. I would try to observe the affects that changes in mv bring about rather than aim for a particuler "high ORP" reading, at least at first till you see where your tank runs with the new equipment. Experiment with what causes the numbers to rise and how effective adding water movement alone (via pump) or using bubbles to move it, or making more or fewer wc's, etc etc and watch the trends rather than the specific numbers.
Then later you can add ozone to raise the numbers if needed.
Good luck,

Kacey

[Automate]

As you can see it was 6:30 pm when I got it online. Spikes in conductivity and ph are when I was fitting the orp sensor inline. I also did a water change 6:30-8 pm so you can see the temperature come up. I don;t know if the ORP followed the temperature rise or it was stabilising. I'll leave it for a couple fo days and do another W/C. I know my ammonia / Nitrite is =0 however my Nitrates are high >40 ppm. So I'll do a 40% water change with heated water and see what the difference is in a couple of days. I did do a calibration check with 400 mV solution and it read ~415 mV before installation. Only thing I don't know if it reads the same if I just place it in the aquarium as apposed to my inline installation. I might also try and reduce the canister flow rate and see if theres a difference.

http://img.photobucket.com/albums/v319/rjconway/orp1.jpg

[kaceyo]

Man, your gonna have alot of fun with with this. Are there connections for monitoring disolved oxygen in your setup? That would be useful when adding meds among other things. Neat!

Kacey

[Automate]

I have been lucky getting good quality ph, orp and conductivity monitors that are industrial grade and have purchased reasonable probes. Dissolved oxygen probes and transmitters are very expensive, I may borrow one from work for a while next time we get one in however could not afford the expense. Oh I work for an industrial instrumentation supplier...

I think I will have to take the probe out and test my aged water as again a water change (only about 15-20%) moved my mV reading down by 30 mV. Difficult to understand these relationships when striving for a orp of ~250 and water changes drive it down :confused: I'm running about 135 mV it was very stable throughout the day & night at ~160mV. I also control the pH via CO2 injection (I have the CO2 airstone under the filter intake so maybe some of the CO2 is getting taken into the canister and effecting the reading of orp on the way through. ?

cheers

[Graham]

Turn the CO2 off and see what happens....add a bit of PP and see what happens

[Automate]

whats pp ?

[jack396]

Oxygen Reduction Potential or Redox...the water ability to oxidize pollutants. It's measured by an electronic meter and the reading is given in millivolts. To have good water the reading should be up in the 350Mv range.

It is not a constant number

Help ?

G

And is this similar to TDS, a reading I have a meter for? For instance, I own a TDS-3 digital meter by HM. I consistently get reading about 163. Does that reading indicate any range for millivolts? Yikes, so much to
learn... with so many different types of readings.

Graham, did you learn all of this (I do know from reading the threads that you are exceedingly knowledgeable on this stuff) by your interest in discus, or did you learn all of this in your formal education pursuits and professional endeavors? Thanks! :confused: :)

[Graham]

Jack I'm a fish nerd...I've had fish since I was a kid, managed pet stores, had a financial interest in pets stores, took science for the short time I was in University, love to read science based ''stuff'', have taken a number of wet labs from different Vets, attend as many seminars as I can while at koi shows................... and have killed a pile of fish over the years...the best teaching tool of all...............:)

Sailinity and TDS meters are very similar to each other, , but I'm not sure that ORP meters are. The first two actually measure dissolved elements in the water, They're based on the waters ability to carry a charge. While an Orp meter measures the waters oxidizing ability....it's ability to oxidize or reduce pollutants. ...both expressed kind of the same way but for different reasons.


PP is potassium permanganate. it's an oxidizer like chlorine or formalin...add it to the water and the ORP reading will go up to 750 Mv or so

G

[jack396]

Graham,

I thank you; keep up the spreading of the knowledge!

Jack:balloon:

[Automate]

OK two tests today..
1. Tue 8:30 did a 30 litre water change, conductivity went down and so did ORP. I run out of kh buffer on the weekend so aged water is very soft, usually add a tablespoon to 100 litres.

1. Wed at midday Increase ph setpoint from 6.2 to 6.3 (ie less CO2 injection) No change to ORP

2. Wed 6 pm turned off UV for 1 hour , could see an effect after about 5 minutes. ORP went down quite fast in fact....turned it back on (7:00pm) and again up it went.

Tomorrow test.
I do not add any ferts to my tank at all, even though it is a planted tank. I just add prime water conditioner to my aged water barrel. Tomorrow I will add 30 ml (tank is 200 litres) of Sera Florena and monitor results.

heres todays trends of pH and Conductivity and orp.

http://img.photobucket.com/albums/v319/rjconway/phincrease.jpg

[kaceyo]

That sounds like an awful lot of KH buffer. Is it because you run C02 that you need to add so much? What KH do you run your tank at?

Kacey

[Automate]

water in Melbourne Australia is very soft....The tank runs at KH 2.5 degrees

[Automate]

Well I just about ran out of sera florena (plant fert) however did get probably< 5 ml out of the bottle. Had an immediate effect at 8:00 am in lowering the orp value and took a number of hours to recover.

http://img.photobucket.com/albums/v319/rjconway/orpfert.png

So at this stage everything I have done actually lowers the value....Still looking for the magic that increases the value. Although talking to others it seems the ORP value increases prior to a filter clean. Maybe I'll just wait it out and see if it naturally goes up. When I installed the unit I did take the opportunity to clean the filter as well.

[Graham]

Add an airstone and gas off the CO2 and see what happens

[Ed13]

I have no clue if ORP is a meaningful parameter, but man this thing sure is cool!!! All measurements are in real time sent to your computer right?
If I had money to spare I'd have one of this in every tank, at least in breeder tanks!

[Automate]

These measurement actually go into a little computer called a linksys NSLU2..only worth US80.00 and it stores the data, and becomes a mini web server. I can call the web site from anywhere and it consumes little power. The cost is in the instruments as the ones that give you an actual output voltage are more expensive than the ones that just display the values.

[gg5190]

What kind of program are you using? How much would it cost to set some thing up like this except for pH, and maby co2? Its really cool, you could keep a tab on your tank from anywhere in the world. ive allways wanted to do this!!!

~regards to Geroge

[Automate]

How cool is this ?...can now tell when my fish get fed and how much...all whilst away from home...Now when I travel I can see when and how much my fish are being fed ! Will be great on holidays and checking if my auto feeder is working OK

http://img.photobucket.com/albums/v319/rjconway/cond1d-1.png


rob

[aquaman3000]

I am also curious about ORP levels in freshwater aquariums. I see many salt ORP levels over 300, but I just setup an ORP probe on a brand new bare aquarium with a wet/dry filter (not cycled) with clean drinkable tap water from a well, and my ORP is around 200ish. Keep in mind, there is absolutely nothing in the bare aquarium or plumbing yet, just water. The PH of the water is 7.8, KH 6, GH 7. If I add Co2, and bring the PH down to 7, the ORP goes up to about 220. This does not seem to jive with the 350mv + readings that have been mentioned here and elsewhere. How are people getting 300+ readings in fresh water?

[Dkarc@Aol.com]

Ozone. Ozone can raise the ORP to perfectly sterile (700+). Not easy to do in a freshwater as there are different techniques needed to introduce the ozone into the water and to maintain contact time. Plus, if not done right, it can be very harmful...not only to the fish, but to you as well.

-Ryan

[Automate]

Just thought I'd give an update...I have setup a larger planted tank and its been running now for 3 weeks...I have just moved the automation across to it and now seeing the orp trend. Now the ORP swings are huge on this tank..a 25% water change will bring it down to ~280 however within 24-48 hours it goes up to 480 mv. I never had such a huge swing in such a short period on my other tank although it was very mature. It will be interesting to see if this is due to my tank not fully cycled, and if the swings in ORP get smaller over time...ORP may actually define a cycled tank. I did move the old canister contents Eheim efistrat (Spelling) into the new filter and lots of the old plants so its not like its completely new. No ammonia and probably 20-30 ppm nitrate, so my filter is running OK

http://img.photobucket.com/albums/v319/rjconway/webshot1.jpg