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Yes, but its not a simple equation and some approximations are needed.
Here' it is in all its glory:
See section 2.2.1, fourth equation down.
I did it a long time ago, but I think I also assumed that Ct scales linearly with CO2 and that the CO2 in the water scales linearly with CO2 in the air (that last part is true at equilibrium).
Check this thread for a generated table of alk, pH, CO2.
Slightly less intimidating than the equation.CO2SYS Marine Tank Table for PH/DKH/CO2
Some of you may have seen a planted tank table I have passed around that shows the relationship between CO2, DKH and PH. Personally this table has really helped me understand my system better hence my attempts to share it. By having my DKH supplement on a doser, skimmer set schedule with outdoor...www.reef2reef.com
You'll find it agrees pretty well with Randy's posted plot.This is exactly what I was looking to generate! Is the table data verified?
The question I am now asking is if this is even beneficial and how locking in pH effects other parameters.
I agree it is an unanswered question, partly because it is harder to control than alk or calcium.
It is the basis for this recent thread of mine:
Alkalinity stability? pH stability? Are they even different?
It is currently the dogma of the reef aquarium hobby to say that alkalinity stability is very important for SPS corals, and that pH is not. Often, the very idea of someone trying to optimize pH is called “chasing numbers” as if that statement by itself shows it to be foolish. Since I have...www.reef2reef.com
@Randy Holmes-Farley I'll read through the thread. As I've chased pH and achieved stability, I'm focused on Alk stability next. I'm targeting 7.6ish. If I switch away from AFR to two-part, I can use my GHL to more easily lock in Alk. I did this when I was doing the Triton method.
Would there be some valuable data I could contribute?
1. Does a stable pH at a fixed alk promote coral growth/health/appearance? Or hurt it?
2. Really interesting to me: if pH is stable, is the alk consumption as focused during the daytime as most folks now report? What if the tank is actually pH reversed, with lower pH during the day. Is the alk still consumed mostly/only during the day?
So I'm not sure I would be able to answer #1. Despite several weeks of very fixed pH, my coral successes has been pretty low. I believe that nutrients, light, and flow still need more work in my tank. I added a Copper Banded Butterfly last week and started overfeeding my tank...my Jellybean Chalice is now growing like crazy. Everything else, not so much.
With regard to #2, I can say I saw no difference in day/night Alk consumption. Then again, it's still a very lightly stocked and new tank.
Last week I also bought some algae barn snake oil (Coraline Algae in a bottle) to see if I can get that growing in the tank. The small rocks and stuff brought from old tank have it, but it hasn't spread.
Reversing day/night pH could easily be achieved...but again I see no day/night alk differences.
This confuses me (though I understand how the math of Alk/pH/CO2 predicts the relationship).My pH was typically swinging between 7.8 - 7.9. In my journey to get that slightly elevated, I ended up being able to lock the pH in day and night +/- .025, but more typically +/- 0.01.
The question I am now asking is if this is even beneficial and how locking in pH effects other parameters.
This led to Randy's articles about pH/CO2/Alk.
With locked in pH, as my Alk rises and falls, my CO2 levels falls and rises.
With my pH of 8.3 (whether it's measured correctly or not) I should be targeting a dKH of 7.6 to maintain normal 350ppm CO2 levels. If I raise my Alk higher, I'm essentially raising the tanks CO2 levels. If I go lower with Alk, I'm essentially lowering CO2 levels below NSW.
This confuses me (though I understand how the math of Alk/pH/CO2 predicts the relationship).
How are you locking in pH in a way that if you run alk higher it pushes CO2 up?
What are your mechanisms for controlling super-stable pH?