Kalk not working as expected

[Randy Holmes-Farley Verified Community Expert]

I cannot get my pH higher than 8.1, even with the CO2 scrubber. What am I doing wrong?

No reason to assume you are doing anything "wrong".

High CO2 air getting into the tank in other ways (such as the tank top) is competing with your Co2 lowering efforts.

 

[Randy Holmes-Farley Verified Community Expert]

stable, high pH is not natural or desirable

It's not natural (but so is alk at 8 dKH unnatural), but desirable is in the eyes of the one deciding what is desirable.

Why do you think it is undesirable? Do you simply assume the ocean parameters are optimal? Why?

 

[Randy Holmes-Farley Verified Community Expert]

Couldn't agree with this more.

I really hate BRS put out the videos on PH. Now all the chem section is, is multiple question on how to raise PH to that magical number. Remember when we could care less what PH number we had?

lol

Ignorance is bliss?

 

[Randy Holmes-Farley Verified Community Expert]

How did you determine how muck Kalk to dose? Also, how often do you change out the CO2 media?

Most folks replace close to all evaporated water with it.

 

[homer1475]

lol

Ignorance is bliss?

Not ignorance, but I also don't need to add 50 things to my tank for that optimal coral growth. I just want to enjoy my tank, not grow corals for profit.

Nothing wrong with a normal PH without chasing it.

 

[EMeyer]

It's not natural (but so is alk at 8 dKH unnatural), but desirable is in the eyes of the one deciding what is desirable.

Why do you think it is undesirable? Do you simply assume the ocean parameters are optimal? Why?

I would never run a reef tank at 8 dKH either; close to 7 appears to be the ideal.

Your point about assuming natural=optimal is a fair point. In some situations, this is not the case, I agree.

But pH levels that fluctuate like natural diel fluctuations have been shown in peer reviewed studies to enhance coral growth. So if we're going for growth alone, I'd favor natural allowing the pH to fluctuate naturally, like it does in the ocean.

But I don't for a second imagine that growth is the only process affected by pH. Lacking perfect knowledge of the system, I favor simulating the natural habitat.

I certainly support everyones' right to experiment with their own tanks. We learn so much from this. My goal in beating this drum is to correct a misconception that a lot of new reefers have. They see "low" (actually normal) pH, and they see fluctuations (which again are normal), and they start looking for solutions to these perceived problems.

I'm trying to remind people that when they try to produce stable high pH in their tanks, they are running an experiment. The default is the ocean. And that is what I think new reefers should aim for, before they start experimenting with other unnatural levels in hopes of optimizing something.

 

[arking_mark]

I would never run a reef tank at 8 dKH either; close to 7 appears to be the ideal.

Your point about assuming natural=optimal is a fair point. In some situations, this is not the case, I agree.

But pH levels that fluctuate like natural diel fluctuations have been shown in peer reviewed studies to enhance coral growth. So if we're going for growth alone, I'd favor natural allowing the pH to fluctuate naturally, like it does in the ocean.

But I don't for a second imagine that growth is the only process affected by pH. Lacking perfect knowledge of the system, I favor simulating the natural habitat.

I certainly support everyones' right to experiment with their own tanks. We learn so much from this. My goal in beating this drum is to correct a misconception that a lot of new reefers have. They see "low" (actually normal) pH, and they see fluctuations (which again are normal), and they start looking for solutions to these perceived problems.

I'm trying to remind people that when they try to produce stable high pH in their tanks, they are running an experiment. The default is the ocean. And that is what I think new reefers should aim for, before they start experimenting with other unnatural levels in hopes of optimizing something.

Natural reef daily pH swings appear to be about +/- 0.5 NBS or less on average:

Alkalinity stability? pH stability? Are they even different?

I have not checked pH in years. I just built a CO2 scrubber and never looked at it again. My tank is so mature that all I really check is Alk and sometimes PO4 every few days to weeks depending on how well my corals look.

www.reef2reef.com

So a realistic reef-like stable target should be something like 8.x +/- 0.5 for your daily swings.

Many tanks see swings of +/- 0.2 or 4x what occurs in our natural reefs.

What's best, who knows?

What we do know based on some some scientific literature and anecdotal evidence:

1. Higher pH --> increased growth is some corals
2. Tanks can be successful from pH 7.8 to 8.6 with daily swings as large as ~0.5

Personally, I chased down pH to increase overall stability.

@Randy Holmes-Farley posted a very interesting thread on what is more stable: https://www.reef2reef.com/threads/alkalinity-stability-ph-stability-are-they-even-different.711768/

In terms of value to maintaining my reef tank, my order is (excluding the basics):

1. Roller Mat
2. ATO
3. AWC
4. Alk controlled automation
5. Salinity controlled automation
6. Auto feeder
7. Automated dosing
8. pH Control

As you see, pH is last on my priority list...and something most shouldn't worry about until they mastered more important stuff.

I think that pH gets a lot of attention because it's also integral to dosing, which many want to start when they setup a tank. The problem is that most don't understand that there is well defined Alk/pH/CO2 model. Meaning given any 2 of these parameters, you can calculate the 3rd.

 

[Randy Holmes-Farley Verified Community Expert]

Not ignorance, but I also don't need to add 50 things to my tank for that optimal coral growth. I just want to enjoy my tank, not grow corals for profit.

Nothing wrong with a normal PH without chasing it.

Of course not. I was addressing your wish that BRS never showed their data.

 

[Randy Holmes-Farley Verified Community Expert]

But pH levels that fluctuate like natural diel fluctuations have been shown in peer reviewed studies to enhance coral growth. So if we're going for growth alone, I'd favor natural allowing the pH to fluctuate naturally, like it does in the ocean.

Not a single study (that I have ever seen) has EVER shown that a variable pH gives better hard coral growth than the same steady pH as the high end of that swing.

Do you know of one?

 

[Reef AquaCult]

Following up on this thread, I am in Florida as well and have the exact same issue. Can someone please help me figure out how to raise my pH. I am dosing kalk via a kalk stirrer daily. With the windows closed, my pH ranges from 7.6 - 7.8. With the windows open, I range from around 7.8 - 8.05. But I obviously am trying to shoot for higher, as I have an SPS dominant tank. My Alk is at 8.9. Any help here would be very much appreciated!!!

Buy a 25 or 50ft air tubing Run it from skimmer behind drywall up into attic, or if you can somehow get it outside even better. My attic has about same co2 levels as outside air. Raised ph from below 7 to nicely above 8

 

[Randy Holmes-Farley Verified Community Expert]

Buy a 25 or 50ft air tubing Run it from skimmer behind drywall up into attic, or if you can somehow get it outside even better. My attic has about same co2 levels as outside air. Raised ph from below 7 to nicely above 8

Your aquarium pH was below 7?

 

[Reef AquaCult]

Your aquarium pH was below 7?

I mean below 8, my mistake. It increased pH by about 0.2-0.3

 

[Plandauesq]

Buy a 25 or 50ft air tubing Run it from skimmer behind drywall up into attic, or if you can somehow get it outside even better. My attic has about same co2 levels as outside air. Raised ph from below 7 to nicely above 8

Very helpful. I’m going to try this.

 

[Plandauesq]

Most folks replace close to all evaporated water with it.

That’s exactly what I’m doing. Randy, based on your formula, if I lower Alk does that result in higher pH? My Alk is presently 9.11

 

[Randy Holmes-Farley Verified Community Expert]

That’s exactly what I’m doing. Randy, based on your formula, if I lower Alk does that result in higher pH? My Alk is presently 9.11

No. Higher alk tends to drive higher pH.