Pegging pH for stable Alk consumption

Operator Wrasse

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By now I think that most serious hobbyists recognize that pH is the largest factor of Alk consumption besides the types of corals in your tank. A pH of 8.3 will have much more carbonate available for skeletal growth as well as it being easier for corals to expel waste from their bodies. Does anyone have experience trying to peg pH for long term Alk stability? I'm not trying to create a science experiment or drive excessive growth. I'm only looking for overall health and stability.

I'm currently planning a 250G mixed tank, LPS dominant, that will have to be fairly hands off. It will be fully automated with a filter roller, AWCs, etc. I have twins on the way and will not have time to commit to manual labor, so it looks like I'll be spending money instead. I have a high level of CO2 in the home from visitors and pets. This means that, depending on the number of people in and out of my house, my pH levels will often fluctuate. This does not include the fact that the windows of my home are open at random times because we fully experience all four seasons in Indiana. With fluctuations in pH come fluctuations in Alk. I can't be hands off of a large system with Alk fluctuations.

Here is my thought process: If I am able to peg pH at any specific number, without major fluctuations, I could stabilize my Alk long term without intervention. Long term, in my eyes, is testing major parameters by hand once every week or two. I have little experience with Kalkwasser as it was too potent for my current 75G softie tank. I was thinking I could primarily dose Kalkwasser with a CO2 scrubber hooked to the skimmer and controlled by a ball valve and pH controller.
 
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on my old 80g below I went about a year and a half where I lost all interest in the hobby. I had so much going on I barely cleaned the glass. The tank flourished thanks to 2 things, my calcium reactor and Alkatronic. These tools make it so easy to keep parameters in check, just something to consider.


7E5D5257-347D-4ADD-A0C3-5683F7E58CF1.png
 

Randy Holmes-Farley

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By now I think that most serious hobbyists recognize that pH is the largest factor of Alk consumption besides the types of corals in your tank. A pH of 8.3 will have much more carbonate available for skeletal growth as well as it being easier for corals to expel waste from their bodies. Does anyone have experience trying to peg pH for long term Alk stability? I'm not trying to create a science experiment or drive excessive growth. I'm only looking for overall health and stability.

I'm currently planning a 250G mixed tank, LPS dominant, that will have to be fairly hands off. It will be fully automated with a filter roller, AWCs, etc. I have twins on the way and will not have time to commit to manual labor, so it looks like I'll be spending money instead. I have a high level of CO2 in the home from visitors and pets. This means that, depending on the number of people in and out of my house, my pH levels will often fluctuate. This does not include the fact that the windows of my home are open at random times because we fully experience all four seasons in Indiana. With fluctuations in pH come fluctuations in Alk. I can't be hands off of a large system with Alk fluctuations.

Here is my thought process: If I am able to peg pH at any specific number, without major fluctuations, I could stabilize my Alk long term without intervention. Long term, in my eyes, is testing major parameters by hand once every week or two. I have little experience with Kalkwasser as it was too potent for my current 75G softie tank. I was thinking I could primarily dose Kalkwasser with a CO2 scrubber hooked to the skimmer and controlled by a ball valve and pH controller.

Some folks are experimenting with stabilizing pH and I'll leave it to them to chime in with the effects they see,

Somewhat unrelated to the exact question of stabilizing pH, but I think the mechanism of increased alkalinity consumption at higher pH is complex and the biological part of the increased consumption is not necessarily due to more carbonate being present. it may equally well be due to increased ease of pumping out H+ when bicarbonate is taken up (which is lower in concentration at higher pH).

We discuss such issues and pH stability here:

 

Stoney

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I've had to keep windows closed almost all day recently due to fires/smoke and found a CO2 scrubber just isnt enough to offset that. Worst part is it's totally random, whatever the wind decides to do that day.

Even at just 600ppm ambient CO2, it wasnt able to maintain my usual pH cycle when CO2 is about 450ppm. Even tested the output of the CO2 scrubber at 70ppm to make sure it wasnt leaking. I do have a lot of surface agitation and an overflow so maybe theres too much gas exchange.
 

arking_mark

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Even with this setup, I'm at best able to keep my pH +/- 0.03. House-level CO2 is constantly changing.

I've also opted to bring down the pH from 8.3 NBS to 8.26 NBS. I may take it down further as there is still a lot of abiotic precipitation.
 
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I've had to keep windows closed almost all day recently due to fires/smoke and found a CO2 scrubber just isnt enough to offset that. Worst part is it's totally random, whatever the wind decides to do that day.

Even at just 600ppm ambient CO2, it wasnt able to maintain my usual pH cycle when CO2 is about 450ppm. Even tested the output of the CO2 scrubber at 70ppm to make sure it wasnt leaking. I do have a lot of surface agitation and an overflow so maybe theres too much gas exchange.

I went with an oversized scrubber that could handle 3x my tank volume...and still can't fully lock in pH.
 

arking_mark

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For me it just seems trying to keep a steady PH is an exercise in futility, much easier to keep Alk stable.

Yes and no.

As noted pH, directly impacts abiotic and biological Cal/ALk consumption.

By not chasing #s, your average daily pH MAY be steady and lead to steady daily Ca/Alk consumption and control.

However, if your home CO2 is more dynamic (your plH will also be more dynamic), your Ca/Alk consumption can be more swingy and harder to control.
 
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on my old 80g below I went about a year and a half where I lost all interest in the hobby. I had so much going on I barely cleaned the glass. The tank flourished thanks to 2 things, my calcium reactor and Alkatronic. These tools make it so easy to keep parameters in check, just something to consider.


7E5D5257-347D-4ADD-A0C3-5683F7E58CF1.png
I can't guess what my consumption rate will be, but I am looking at going with primarily dosing Kalkwasser through a reactor and adding a Calcium Reactor if I cannot meet my consumption needs. I will definitely have automatic testing of some sort for at least Alk.

Some folks are experimenting with stabilizing pH and I'll leave it to them to chime in with the effects they see,

Somewhat unrelated to the exact question of stabilizing pH, but I think the mechanism of increased alkalinity consumption at higher pH is complex and the biological part of the increased consumption is not necessarily due to more carbonate being present. it may equally well be due to increased ease of pumping out H+ when bicarbonate is taken up (which is lower in concentration at higher pH).

We discuss such issues and pH stability here:


Thank you for putting this so eloquently. You've done a much better job at explaining these principles than I ever could.


Even with this setup, I'm at best able to keep my pH +/- 0.3. House-level CO2 is constantly changing.

I've also opted to bring down the pH from 8.3 NBS to 8.26 NBS. I may take it down further as there is still a lot of abiotic precipitation.

I will definitely read through this tonight! I'm not looking for a consistent number, but something with the smallest reasonable fluctuation such as +/- 0.2. I'm picking an arbitrary number because I've always heard that a 0.2 fluctuation is reasonable. A +/- 0.3 daily fluctuation could be completely reasonable depending on professional opinion.
 
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Yes and no.

As noted pH, directly impacts abiotic and biological Cal/ALk consumption.

By not chasing #s, your average daily pH MAY be steady and lead to steady daily Ca/Alk consumption and control.

However, if your home CO2 is more dynamic (your plH will also be more dynamic), your Ca/Alk consumption can be more swingy and harder to control.
That is the issue I'm currently dealing with in my softie tank. I have too much instability and have just gone back to old school weekly water changes to balance my parameters. If I'm having these issues now, I'm assuming they will continue in a new home with the addition of kids.
 

arking_mark

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I can't guess what my consumption rate will be, but I am looking at going with primarily dosing Kalkwasser through a reactor and adding a Calcium Reactor if I cannot meet my consumption needs. I will definitely have automatic testing of some sort for at least Alk.



Thank you for putting this so eloquently. You've done a much better job at explaining these principles than I ever could.



I will definitely read through this tonight! I'm not looking for a consistent number, but something with the smallest reasonable fluctuation such as +/- 0.2. I'm picking an arbitrary number because I've always heard that a 0.2 fluctuation is reasonable. A +/- 0.3 daily fluctuation could be completely reasonable depending on professional opinion.

I missed a zero in my stability...I'm +/- 0.03 NBS. Updated post as well. 8.23 - 8.29 NBS with an 8.26 set point.
 
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I missed a zero in my stability...I'm +/- 0.03 NBS. Updated post as well. 8.23 - 8.29 NBS with an 8.26 set point.
I just read through your thread. To me, that is incredibly successful from a hobbyist standpoint. We aren't working in a controlled lab environment, so I would say that you definitely have pH "pegged". I was hoping for +/- 0.1 pH fluctuations to be the ultimate stability. I'm glad to see it is more than possible. Do you think that your setup is worth the Alk stability?
 
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Some folks are experimenting with stabilizing pH and I'll leave it to them to chime in with the effects they see,

Somewhat unrelated to the exact question of stabilizing pH, but I think the mechanism of increased alkalinity consumption at higher pH is complex and the biological part of the increased consumption is not necessarily due to more carbonate being present. it may equally well be due to increased ease of pumping out H+ when bicarbonate is taken up (which is lower in concentration at higher pH).

We discuss such issues and pH stability here:

Randy,

I genuinely love your work. It reminds me of my time as an engineering student at Purdue and my countless hours in chem and physics labs. I just read through the first post of the thread and I'm loving it. Thank you for your contributions to this hobby.
 

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I just read through your thread. To me, that is incredibly successful from a hobbyist standpoint. We aren't working in a controlled lab environment, so I would say that you definitely have pH "pegged". I was hoping for +/- 0.1 pH fluctuations to be the ultimate stability. I'm glad to see it is more than possible. Do you think that your setup is worth the Alk stability?

I think you mean the pH stability.

Do I like my setup? Yes and no. I was working towards a ULM system and this definately ups the maintenance.

Is it worth it? Definitely not, unless you like experimenting. I've seen many successful tanks that don't chase pH stability.

Once the tank is fully matured with coral, I'm likely to try and simplify things. I'd love to get rid of the skimmer and switch to just AFR for dosing.
 

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On my 120 ph is 7.9- 8.2, night vs day with no issues.
Alk is stable at 7.5. My desired alk range is 7-8.
I run a carx and would recommend one on a system your size.
My system is pretty hands off.
I change 7" filter sock twice a week.
I ran a filter roller but took it offline. I may have not had it installed right as it let alot of detrius pass. Will revisit that one soon.
Empty skimmer cup once a week.
I dose trace daily, takes less than a minute, and thats it.
12 gal WC every 2 months.
20210809_140017.jpg
 
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I think you mean the pH stability.

Do I like my setup? Yes and no. I was working towards a ULM system and this definately ups the maintenance.

Is it worth it? Definitely not, unless you like experimenting. I've seen many successful tanks that don't chase pH stability.

Once the tank is fully matured with coral, I'm likely to try and simplify things. I'd love to get rid of the skimmer and switch to just AFR for dosing.
I meant Alk. I just assumed that because your pH is incredibly stable, your Alk probably is, too, but it seems like stable Alk was never a huge issue for you.
 

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I meant Alk. I just assumed that because your pH is incredibly stable, your Alk probably is, too, but it seems like stable Alk was never a huge issue for you.

Alk stability is there, but when something goes offline even for maintenance it has an Alk impact.

My skimmer was offline for several hours for some maintenance and pH dropped to 8.12. My next Alk reading went from 7.7 to 8.0.

Another reason to maybe just not chase it.
 
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Alk stability is there, but when something goes offline even for maintenance it has an Alk impact.

My skimmer was offline for several hours for some maintenance and pH dropped to 8.12. My next Alk reading went from 7.7 to 8.0.

Another reason to maybe just not chase it.
Did your Alk stabilize back to 7.7 after that or did you have to take active measures to begin to lower it?
 

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