ORP / Redox Meters. Any Info please....

Anyone here use one for freshwater aquariums? Can ayone explain waht the readings mean in terms of water quality i.e. good or bad. What effects the ORP reading etc.

Googling has been of little help so far, articles usually are very technical or relate to non aquarium scenarios.

Any help appreciated.


Daragh

All i know is Orp (oxygen reduction potential) or Redox is the amount of usable oxygen in your tank and is measured in mv (millivolts )
In Marine tanks anywhere from 250mv - 450mv is acceptable.
I dont know the levels for fresh water.

If you have a low orp level and a high kh it will make your fish more adhesive to external parasites. Some recon this so called Discus plague can be controlled by a high orp level and a low kh.
Don`t know he levels either.

That's interesting Anthony, didn't know that. Hard to find out anything about ORP, relating to freshwater fishkeeping.

I am getting readings between 40 and 80 approx from a variety of tanks. My water is very soft 3-4 KH from the tap and as low as 1 KH in some breeding tanks.

I am trying to get my head around the relationship between various water parameters and how to control them. Guess I should have listened harder in school.


Daragh

Tanks with a kh of 1 are liable to crash. It is not stable enough to maintain a constant pH, especially if you nitrate rises.
Nitrate is nitric acid and will eat into you kh causing your pH to drop.

Tanks with a kh of 1 are liable to crash. It is not stable enough to maintain a constant pH, especially if you nitrate rises.
Nitrate is nitric acid and will eat into you kh causing your pH to drop.

Yes and no, indirectly yes the bacteria used in nitrification produce as a by product acid, ironically de nitrating bacteria do the opposite, hence if you dont get a NO3 rise (without doing water changes) in a marine tank the pH wont drop as these critter rise the pH in direct portion to the other crittres that drop the pH, this is normally done by having volcanic rock or life rock or in a freshwater tank a deep sand bed/planted tank.

Tanks with a kh of 1 are liable to crash. It is not stable enough to maintain a constant pH, especially if you nitrate rises.
Nitrate is nitric acid and will eat into you kh causing your pH to drop.

Yes and no, indirectly yes the bacteria used in nitrification produce as a by product acid, ironically de nitrating bacteria do the opposite, hence if you dont get a NO3 rise (without doing water changes) in a marine tank the pH wont drop as these critter rise the pH in direct portion to the other crittres that drop the pH, this is normally done by having volcanic rock or life rock or in a freshwater tank a deep sand bed/planted tank.

But your talking about Anerobic bacteria that nutrifies nitrate and turns it in to a harmless gas. You would not get this in an external/internal filther unless you were using Siporax and or a pad/balls that you never cleaned and allowed it to become filthy therefore creating an inviroment for anerobic bacteria to survive.

Your wetdry filther (is that correct) uses a gravel base compacted to allow anerobic bacteria to survive and youe aerobic bacteria is taking oxygen from the enviroment instead of the tank water so the oxygen level in the tank stays high with a better chance of sustaining a high pH.

Is oxygen a bi product of anerobic bacteria.

@ Anthony

oygen is not a buy product of anaerobic digestion.
Most anaerobic bacteria go digest going down the lactic fermentation.

Chemically it looks like this if memory serves me right:

C6 H12 O6 + C10 H15 N5 O10 P2 +2 PO4 3- → 2C2 H5OH+2CO2+2 C10 H16 N5 O3 P3.

Before anybody starts off counting atoms, I might be not completely correct but you might want to check with Sushi. He's doing bio chemistry in college and the last time I sat through a bio chem lecture was back in 1992

Holger

Tanks with a kh of 1 are liable to crash. It is not stable enough to maintain a constant pH, especially if you nitrate rises.
Nitrate is nitric acid and will eat into you kh causing your pH to drop.

Yes and no, indirectly yes the bacteria used in nitrification produce as a by product acid, ironically de nitrating bacteria do the opposite, hence if you dont get a NO3 rise (without doing water changes) in a marine tank the pH wont drop as these critter rise the pH in direct portion to the other crittres that drop the pH, this is normally done by having volcanic rock or life rock or in a freshwater tank a deep sand bed/planted tank.

But your talking about Anerobic bacteria that nutrifies nitrate and turns it in to a harmless gas. You would not get this in an external/internal filther unless you were using Siporax and or a pad/balls that you never cleaned and allowed it to become filthy therefore creating an inviroment for anerobic bacteria to survive.

Your wetdry filther (is that correct) uses a gravel base compacted to allow anerobic bacteria to survive and youe aerobic bacteria is taking oxygen from the enviroment instead of the tank water so the oxygen level in the tank stays high with a better chance of sustaining a high pH.

Is oxygen a bi product of anerobic bacteria.

The bacteria that changes ammonia to nitrite and then to nitrate as a by product of their action create acid, so in a way you are right what you stated in the first place, anaerobic bacteria (change nitrate back into nitrogen gas also as I bi product of their action actually increase the pH, in a ideal world the pH would not change in a enclosed system, in reality nitrate normally rises and pH drops.

@ Anthony

oygen is not a buy product of anaerobic digestion.
Most anaerobic bacteria go digest going down the lactic fermentation.

Chemically it looks like this if memory serves me right:

C6 H12 O6 + C10 H15 N5 O10 P2 +2 PO4 3- → 2C2 H5OH+2CO2+2 C10 H16 N5 O3 P3.

Before anybody starts off counting atoms, I might be not completely correct but you might want to check with Sushi. He's doing bio chemistry in college and the last time I sat through a bio chem lecture was back in 1992

Gee Holger you have go a good memory to rember that forula
I just start with counting the carbon atoms and both sides dont balance, so I did not bother to continue:roll: dont you think if you are going to be that technical you should put underneath C=carbon P=...etc etc
May be half the pople wont not have the faintest what this is all about.

Holger

My apoligies Sean,
made a bit of a mess of this one

Should look like this

C6 H12 O6+2 C10 H15 N5 O10 P2 ( Adenosine diphosphate or ADP)+ 2 PO4 3- → 2 C3H6 O3 (lactic acid) + 2 C10 H16 N5 O13 P3 ( Adenosine 5'-triphosphate or ATP)

Got it somewhat mixed up with the alcohol fermentation. As I said it's been some time

Thanks for that Holger, we all feel better off after that

Lets cast a vote though to clarify it all.

www.irishfishkeepers.com/forum/viewtopic.php?t=1387

Thanx for the info guys, but have to admit that formula means nothing to me. I was aware of the pH stability issue Anto mentioned...

My tap water is soft, which suits for breeding Corys, so how do I ensure a stable envirnoment with a low pH (around 6) with low KH without plants and or sand substrate? My Cory breeding tanks are bare apart from a small bit of bogwood and small portion of Java Moss?

And back to the original Query, how to Interpret ORP readings?


Daragh

Thanx for the info guys, but have to admit that formula means nothing to me. I was aware of the pH stability issue Anto mentioned...

My tap water is soft, which suits for breeding Corys, so how do I ensure a stable envirnoment with a low pH (around 6) with low KH without plants and or sand substrate? My Cory breeding tanks are bare apart from a small bit of bogwood and small portion of Java Moss?

And back to the original Query, how to Interpret ORP readings?


Daragh

Hi Daragh,
on fresh farms I have worked in in Tampa Florida I have never seen any one bothering with the redox potential, however in you current senior I can see why you are nervous about a sudden pH, and lats face it with no buffering it could really drop fast, bearing in mind a drop of more than 1.3pH in the negative direction cause problems for the fish as no matter how much they increase their respiration rate the blood cells that flow around their blood cannot carry oxygen (borr effect).

So whats the solution?

Well the bog wood is not that dangerous as its given out a very small amount of acid in a even way, whats a big no no on a tropical fish farm though is the java moss, as its alive it increases the pH in the day time, then rapidly decreases the pH at night, the pH is at its lowest just before lights on, hence on a professional tropical fish farm they use mops (as in cleaning the floor mops) and synthetic mesh which looks almost identical to real jave moss, a hotel or factory food preparation company that sells to these trades would have this mesh.

getting back to the redox thing well its all abit complicated, lets look at it from a lay mans perspective, if I use an electricians multimeter (yellow thing for testing for voltage and resistance) I set it up to measure resistance and hold one probe pinched in one hand and the other probe held in the other, I can actual test the resistance in my body, each day I test it I will have a different level, e.g if I work a 14 hour day and dont drink I will have more resistance (more salt in my blood) if I have been drinking the night before I will have even more resistance, if I have ther flue or been a a lot of pain over several days I would have even more resistance.

Well basically aquarium water that is clean has more millivolts than dirty water, and beside a radio broadcast station it will have more millivolts than far away from the transmitter.

still dont understand?

O.K I will make it even simpler. The synthetic mesh which acts as java moss without the risk of a pH drop cost say 20 euros, and you dont have to wast time measuring redox, as opposed to the redox machine which is a lot more than 20 euros.

Thanx Fr Jack, I understood that

I will get some spawning mops instead of Jave Moss asap. I have halved the quantity in each tank in the meantime.

After buying a Bluelab Combo meter that does pH, TDS & Temp I was so pleased with it I was looking out for any other meters (hoping the was such a think as NO2 / NO3 meter) I bought an ORP meter on the basis of this description:

ORP - Mv meters are the most accurate way of testing for your water quality and bio load, which is very important for judging when to do water changes and to make sure nothing is starting to go wrong. The higher the reading the ORP reading the better quality your water is and visa versa. these meters are invaluable in knowing the health of your tank or pond.

Guess I should not believe everything I read.



Daragh

Daragh,

I wouldn't worry about a pH crash too much even with Java moss in it. My tapwater is also very soft and I have plenty of plants and moss in my tanks and never had a pH crash. I know people who use pure RO water and never suffered a crash. I have kept discus and angels in pure RO water with no adverse effects. The bioload was much higher in my growing-on tanks than you will ever have with your corys.
Some corys actually need a pH crash to stimulate spawning

Holger

A low stocking level and frequent w/c`s will keep your water stable.
When I kept Discus I got in to all the techy crap.
Thank God I am an idiot and I forgot most of it now
I became a very boring person. People would ask you questions and they would be yawning while you answered them. Only joking.
Its not worth the hassle and thats when you start having problems.
KISS is the best method.
KEEP IT SIMPLE STUPID.

Keep a safe stocking level and do regular water changes.