Aquarium pH Distilled

[Canadianreefmaster]

The pH and alkalinity are directly related in the same way that C02 and pH in the human body are regulated. Check out C02 exchange and the acid base buffer system (kidneys/lungs), Been a long day at work. Trying to skim through. There are a number of factors that you will consider.

1) ph and temperature relation (dissolved oxygen and co2 are dependent on temp to a smaller degree, increase temp can be more difficult for oxygen to remain in water, this Co2 accumulates (directly proportional)

2) Environmental C02 (yes it increases and decreases) for this the alkalinity is buffering this through the equation
HA(aq) +OH- (aq) ---> A- (aq) + h20 (l)
Ha(aq) + H20(l) ---> A- (aq ) + H+

where Ka= (H+)(A-)/(HA)--> [H+] =kA (HA)/A-)

within the H+ HCO3- <--> h2C03 <--> C02 + H20

when you have CO2 it is the acid (HA) that pushes the equilibrium back towardS HC03-

As you push the equilibrium to maintain the buffer capacity it shifts and causes the formation of a Precipitate with C02.
and a result of pH will drop within the buffer system as it shifts to deal with the C02

If you live in a city you will have higher C02 you may have more difficulty buffering the alkalinity (as you are precipitating out C02 to keep the ph buffer capacity).

3) Strontium and other elements, these are also part of your buffer system. Low strontium may result in poor buffering or increase CO2 and thus decrease in pH

4) You looked at your tank funny and its mad at you....

5) Bicarbonate - drops ph over a few hours then it will increase again and will functionally alter the ph pretty much regardless of C02 level in atmosphere.

6)number of fish and metabolic processes


The list goes on, however it becomes minor things that an aquarist can't manage (ie. bacterial blooms) increase nutrient breakdown by bacteria from over feeding...

The main thing is ... My aquarium is harder to look after than my ICU patients.

But ph and alkalinity are a direct relation to C02 in the same means of that of the kidneys buffering c02 in our body. as per the math equation above if you like that stuff. factors outside of the dissolved C02...ie., temp, minor elements (or salinity i should say), metabolic processes in the tank and outside the tank. However the most important one really is the relation of PH, C02 and alkalinity.

(check out youtube kidney acid base buffer systems to understand PH and Buffers) it will be helpful and what I use to teach this buffer system to students.

 

[Canadianreefmaster]

The pH and alkalinity are directly related in the same way that C02 and pH in the human body are regulated. Check out C02 exchange and the acid base buffer system (kidneys/lungs), Been a long day at work. Trying to skim through. There are a number of factors that you will consider.

1) ph and temperature relation (dissolved oxygen and co2 are dependent on temp to a smaller degree, increase temp can be more difficult for oxygen to remain in water, this Co2 accumulates (directly proportional) however, we keep our tanks at constant temp (so not huge factor)

2) Environmental C02 (yes it increases and decreases) for this the alkalinity is buffering this through the equation
HA(aq) +OH- (aq) ---> A- (aq) + h20 (l)
Ha(aq) + H20(l) ---> A- (aq ) + H+

where Ka= (H+)(A-)/(HA)--> [H+] =kA (HA)/A-)

within the H+ HCO3- <--> h2C03 <--> C02 + H20

when you have CO2 it is the acid (HA) that pushes the equilibrium back towardS HC03-

As you push the equilibrium to maintain the buffer capacity it shifts and causes the formation of a Precipitate with C02.
and a result of pH will drop within the buffer system as it shifts to deal with the C02

If you live in a city you will have higher C02 you may have more difficulty buffering the alkalinity (as you are precipitating out C02 to keep the ph buffer capacity).

3) Strontium and other elements, these are also part of your buffer system. Low strontium may result in poor buffering or increase CO2 and thus decrease in pH

4) You looked at your tank funny and its mad at you....


but for reef chemistry for the general reefer. C02 in the water is the only thing that needs to really be considered, HOWEVER, its not the ONLY consideration there are others. The rest is all minor effects.

The main thing is ... My reef aquarium is harder to look after than my ICU patients with an acid base buffer system issue.

(check out youtube kidney acid base buffer systems to understand PH and Buffers) it will be helpful and what I use to teach this buffer system to students when i taught animal physiology/biology/ecology in at the University of Victoria .

 

[arking_mark]

Hi - thanks - I didnt make my question clear. I am aware that aeration (i.e. dissolved CO2) in the water will affect the pH. The question related more to 'is there any time where the Alkalinity, pH and CO2 relationship can be askew. So - lets I'll use different numbers than in my original question lets say the alkalinity is 10, the CO2 levels are low (i.e. maximally aerated), would there be any possibility for the pH to be lets say 7.5. Or by definition would it have to be higher. (My strong assumption is the pH would have to be higher). I was just curious

I can run any numbers you'd be interested in....your air CO2 would need to be 3750ppm.

If you had normal indoor air quality....your pH would be around 8.2

So unless you have an aeration problem, low-pH additive, highly overstocked tank, or very high CO2 levels, 10 Alk and 7.5 pH is not acheivable.

 

[Randy Holmes-Farley]

The pH and alkalinity are directly related in the same way that C02 and pH in the human body are regulated. Check out C02 exchange and the acid base buffer system (kidneys/lungs), Been a long day at work. Trying to skim through. There are a number of factors that you will consider.

1) ph and temperature relation (dissolved oxygen and co2 are dependent on temp to a smaller degree, increase temp can be more difficult for oxygen to remain in water, this Co2 accumulates (directly proportional) however, we keep our tanks at constant temp (so not huge factor)

2) Environmental C02 (yes it increases and decreases) for this the alkalinity is buffering this through the equation
HA(aq) +OH- (aq) ---> A- (aq) + h20 (l)
Ha(aq) + H20(l) ---> A- (aq ) + H+

where Ka= (H+)(A-)/(HA)--> [H+] =kA (HA)/A-)

within the H+ HCO3- <--> h2C03 <--> C02 + H20

when you have CO2 it is the acid (HA) that pushes the equilibrium back towardS HC03-

As you push the equilibrium to maintain the buffer capacity it shifts and causes the formation of a Precipitate with C02.
and a result of pH will drop within the buffer system as it shifts to deal with the C02

If you live in a city you will have higher C02 you may have more difficulty buffering the alkalinity (as you are precipitating out C02 to keep the ph buffer capacity).

3) Strontium and other elements, these are also part of your buffer system. Low strontium may result in poor buffering or increase CO2 and thus decrease in pH

4) You looked at your tank funny and its mad at you....


but for reef chemistry for the general reefer. C02 in the water is the only thing that needs to really be considered, HOWEVER, its not the ONLY consideration there are others. The rest is all minor effects.

The main thing is ... My reef aquarium is harder to look after than my ICU patients with an acid base buffer system issue.

(check out youtube kidney acid base buffer systems to understand PH and Buffers) it will be helpful and what I use to teach this buffer system to students when i taught animal physiology/biology/ecology in at the University of Victoria .

How do you think strontium relates to seawater pH buffering? I do not believe it is any significant contribution to pH effects at pH 8 in seawater.

Interesting that you taught the physiologic buffer system. One of my real world contributions is the co-invention of a couple of oral drugs (polymers) to bind phosphate for kidney disease patients. The first of these was sevelamer hydrochloride. After it was on the market, some docs expressed an interest in a form that would provide more pH buffering for CKD patients not on dialysis who have acidosis as a concern. Developing a new form of the polymer that provided bicarbonate/carbonate instead of chloride provided this benefit, and sevelamer hydrochloride (Renagel) was mostly displaced in use by docs with this new form, sevelamer carbonate (Renvela).

 

[MnFish1]

The pH and alkalinity are directly related in the same way that C02 and pH in the human body are regulated. Check out C02 exchange and the acid base buffer system (kidneys/lungs), Been a long day at work. Trying to skim through. There are a number of factors that you will consider.

1) ph and temperature relation (dissolved oxygen and co2 are dependent on temp to a smaller degree, increase temp can be more difficult for oxygen to remain in water, this Co2 accumulates (directly proportional)

2) Environmental C02 (yes it increases and decreases) for this the alkalinity is buffering this through the equation
HA(aq) +OH- (aq) ---> A- (aq) + h20 (l)
Ha(aq) + H20(l) ---> A- (aq ) + H+

where Ka= (H+)(A-)/(HA)--> [H+] =kA (HA)/A-)

within the H+ HCO3- <--> h2C03 <--> C02 + H20

when you have CO2 it is the acid (HA) that pushes the equilibrium back towardS HC03-

As you push the equilibrium to maintain the buffer capacity it shifts and causes the formation of a Precipitate with C02.
and a result of pH will drop within the buffer system as it shifts to deal with the C02

If you live in a city you will have higher C02 you may have more difficulty buffering the alkalinity (as you are precipitating out C02 to keep the ph buffer capacity).

3) Strontium and other elements, these are also part of your buffer system. Low strontium may result in poor buffering or increase CO2 and thus decrease in pH

4) You looked at your tank funny and its mad at you....

5) Bicarbonate - drops ph over a few hours then it will increase again and will functionally alter the ph pretty much regardless of C02 level in atmosphere.

6)number of fish and metabolic processes


The list goes on, however it becomes minor things that an aquarist can't manage (ie. bacterial blooms) increase nutrient breakdown by bacteria from over feeding...

The main thing is ... My aquarium is harder to look after than my ICU patients.

But ph and alkalinity are a direct relation to C02 in the same means of that of the kidneys buffering c02 in our body. as per the math equation above if you like that stuff. factors outside of the dissolved C02...ie., temp, minor elements (or salinity i should say), metabolic processes in the tank and outside the tank. However the most important one really is the relation of PH, C02 and alkalinity.

(check out youtube kidney acid base buffer systems to understand PH and Buffers) it will be helpful and what I use to teach this buffer system to students.

My question related to what if you're adding an additional buffer to the equation. Will that shift the curve some. I.e. adding more borate as compared to carbonate. Seems like it would. The equations, etc are for use in pure solutions. But if someone is adding lets say that borate buffer to get the pH to 8.3. Does that (or anything else) affect the predictions made in the OP. My guess is probably not.

 

[MnFish1]

I can run any numbers you'd be interested in....your air CO2 would need to be 3750ppm.

If you had normal indoor air quality....your pH would be around 8.2

So unless you have an aeration problem, low-pH additive, highly overstocked tank, or very high CO2 levels, 10 Alk and 7.5 pH is not acheivable.

I don't have a problem at all... I was asking a theoretical question. Are there any other chemicals that can shift the equilibrium further in one direction - i.e. the addition of borate buffers, etc etc.

 

[arking_mark]

For those interested in natural pH levels in our ocean reefs. Note that the pH is Total and not NBS.

Post in thread 'Alkalinity stability? pH stability? Are they even different?' https://www.reef2reef.com/threads/a...y-are-they-even-different.711768/post-9382573

 

[GuppyHJD]

Randy - my ALK moves from 9.0 to 10.1 but my pH is not moving at all - API test 8.0. I am going to try the cup of water test but have to wait until late at night and the outside temp is closer to my aquarium temp (currently above 90 degrees outside in Florida).
For aeration in my tank, I am relying on the skimmer and to some extent my two powerheads and surface exchange. Any benefit or reason not to just put a simple air stone in my sump and let it bubble away?
I am trying to determine if I run a tube outside from my skimmer air intake will help - the issue has been a) how to route it (into attic or not) or into garden next to house (spraying) b) would outside air being 10-15 degrees about inside air alter the pH also?

The biggest question currently is - what pH meter(s) do you recommend? My API test and my LFS test is showing 8.0 pH all the time.

 

[arking_mark]

Randy - my ALK moves from 9.0 to 10.1 but my pH is not moving at all - API test 8.0. I am going to try the cup of water test but have to wait until late at night and the outside temp is closer to my aquarium temp (currently above 90 degrees outside in Florida).
For aeration in my tank, I am relying on the skimmer and to some extent my two powerheads and surface exchange. Any benefit or reason not to just put a simple air stone in my sump and let it bubble away?
I am trying to determine if I run a tube outside from my skimmer air intake will help - the issue has been a) how to route it (into attic or not) or into garden next to house (spraying) b) would outside air being 10-15 degrees about inside air alter the pH also?

The biggest question currently is - what pH meter(s) do you recommend? My API test and my LFS test is showing 8.0 pH all the time.

I know you asked @Randy Holmes-Farley but here are a couple of thoughts...

• API test kit for pH is probably not very accurate
• Working with your assumed 8pH and 9dKH, your indoor CO2 would be roughly 900. Going from 9-->10dKH and keeping the CO2 at 900 would only raise pH by about 0.04....which the API may not be accurate enough to read.
• However, CO2 levels usually change greatly throughout the day...and will have a greater impact on your pH

 

[GuppyHJD]

I know you asked @Randy Holmes-Farley but here are a couple of thoughts...

• API test kit for pH is probably not very accurate
• Working with your assumed 8pH and 9dKH, your indoor CO2 would be roughly 900. Going from 9-->10dKH and keeping the CO2 at 900 would only raise pH by about 0.04....which the API may not be accurate enough to read.
• However, CO2 levels usually change greatly throughout the day...and will have a greater impact on your pH

arking_mark
Thank you.
Hopefully I will have a digital pH pen that will show the difference. I am going to try the aeration test indoor/outdoor later tonight.

 

[Randy Holmes-Farley]

Randy - my ALK moves from 9.0 to 10.1 but my pH is not moving at all - API test 8.0. I am going to try the cup of water test but have to wait until late at night and the outside temp is closer to my aquarium temp (currently above 90 degrees outside in Florida).
For aeration in my tank, I am relying on the skimmer and to some extent my two powerheads and surface exchange. Any benefit or reason not to just put a simple air stone in my sump and let it bubble away?
I am trying to determine if I run a tube outside from my skimmer air intake will help - the issue has been a) how to route it (into attic or not) or into garden next to house (spraying) b) would outside air being 10-15 degrees about inside air alter the pH also?

The biggest question currently is - what pH meter(s) do you recommend? My API test and my LFS test is showing 8.0 pH all the time.

Maybe it is pH 8.0 all the time, but a test kit is not a good way to gauge.

Any calibrated pH meter can do the job. Two or more point calibration is best.

Here's what I suggest:

Aquarium Chemistry: Measuring pH with a Meter

This article describes how pH meters work, how to select one to use, and how to best use it to measure the pH of a reef aquarium.

reefs.com

 

[GuppyHJD]

Maybe it is pH 8.0 all the time, but a test kit is not a good way to gauge.

Any calibrated pH meter can do the job. Two or more point calibration is best.

Here's what I suggest:

Aquarium Chemistry: Measuring pH with a Meter

This article describes how pH meters work, how to select one to use, and how to best use it to measure the pH of a reef aquarium.

reefs.com

Thank you. I received a pH test meter today. I am working on calibrating it.

 

[GuppyHJD]

Maybe it is pH 8.0 all the time, but a test kit is not a good way to gauge.

Any calibrated pH meter can do the job. Two or more point calibration is best.

Here's what I suggest:

Aquarium Chemistry: Measuring pH with a Meter

This article describes how pH meters work, how to select one to use, and how to best use it to measure the pH of a reef aquarium.

reefs.com

Very helpful article. Thank you