ACI Kalkwasser Method.... I've watched this video and read a few articles, still not sure the exact method.

[drawman]

Most alk consumption is during the daytime hours. If you dose all or mostly at night to stabilize pH, you end up with very swingy alk.

That's why it is so hard to stabilize alk and pH at the same time. It really cannot be done by dosing alone (except in a super high aerated tank with no pH swing), and probably needs CO2 level control in the air used for aeration.

I wonder if you had a constant pH if calcification rate would be constant at night versus day. I looked up a journal article on the subject of calcification rate at night vs day but it wasn't clear that they controlled pH.

 

[Randy Holmes-Farley]

I wonder if you had a constant pH if calcification rate would be constant at night versus day. I looked up a journal article on the subject of calcification rate at night vs day but it wasn't clear that they controlled pH.

It's an unknown, IMO. It is apparent from many folks with automatic measuring and dosing of alk that alk declines mostly during the daylight hours in tanks with substantial hard corals. That is also known in the scientific literature.

Photosynthesis and Calcification at Cellular, Organismal and Community Levels in Coral Reefs: A Review on Interactions and Control by Carbonate Chemistry1

Abstract. SYNOPSIS. Photosynthesis and calcification in zooxanthellate scleractinian corals and coral reefs are reviewed at several scales: cellular (pathw

academic.oup.com

"Photosynthesis and calcification are tightly coupled in zooxanthellate scleractinian corals and coral reef communities. Calcification is, on average, three times higher in light than in darkness.."


What is not apparent is precisely why.

Is it driven directly by light inside of corals? Some articles like the one above suggest this is the case.

Alternatively, is it driven by the higher pH during the daylight due to photosynthesis driving up the pH? It is easier for corals to get rid of excess H+ from calcification when pH is higher.

Finally, is abiotic precipitation driving a part of the daily consumption in many tanks, with that being primarily during the higher pH daylight hours?

The real answer for any given reef tank might be some combination of all three of these.

My dream experiment is for someone to run a reef tank on a reverse pH cycle, so pH is lower during the daylight hours but alkalinity is steady, and quantify when alkalinity is consumed. It is not a trivial experiment. It would help distinguish these mechanistic possibillities.

 

[Koigula]

Most alk consumption is during the daytime hours. If you dose all or mostly at night to stabilize pH, you end up with very swingy alk.

That's why it is so hard to stabilize alk and pH at the same time. It really cannot be done by dosing alone (except in a super high aerated tank with no pH swing), and probably needs CO2 level control in the air used for aeration.

I checked the alkalinity at 7 am as 2 part starts at 8 am. I got a 143 ppm as CaCO3 (8.31 pH) instead of 148 ppm as CaCO3 at 8:30 pm (8.37 pH).

I do have a 36" venturi skimmer with 1900 gph pump and air exchange in room and reverse daylight 14 gallon chaeto refugium with ocean direct sand. I'll have to check it some more before leaving this set up alone. Everything seems pretty good and observing corals I see growth and no signs of stress. I am excited the Mike Palleta blue is recovering.

 

[fushi]

ACI Method.... I've watched this video and read a few articles, still not sure the exact method.

I don‘t think you will get the exact method out of Chris because I don‘t think he fully understands what he’s doing chemically. I am not claiming I do either but on my quest for better PH I have spent a lot of time experimenting on my tank, reading @Randy Holmes-Farley posts, and have come to a few conclusions.

1. It does not matter what hydroxide you dose, they all provide the same ph boost per unit of alk.
Calcium hydroxide, sodium hydroxide, potassium hydroxide all provide the same. So Chris mixing hydroxides and keeping some secret doesn’t really make sense. Nor does using potassium hydroxide unless your tank uses a ton of potassium (mine does not).

according to randy
” The immediate effect on pH for dosing 1.4 dKH of each additive is about:
hydroxide 0.66 pH units (calcium or sodium, doesn't matter)
carbonate 0.34
bicarbonate -0.04 ”

2. Chris seems to have come to some anecdotal conclusions that I have also; such as when you have good PH stability, instability of other parameters have less of a detrimental effect. When my ph stays above 8.25, alk swings, nutrient swings, etc. don't seem to affect my sensitive corals, but as soon as my PH drops to around 8.1 any instability throws them into stn/rtn.

So dosing a hydroxide at night will give a greater alk swing than dosing over a 24 hour period but the 8.3 Ph stability may mitigate any detrimental effects of the alk swing.

With my tank I try to keep everything stable but put more care into keeping my PH at 8.3 +/- 1.5
I do keep a close eye on Alk, and don’t let it swing more than 1 dkh (but it usually doesn’t swing more than 0.5 daily)

I dose sodium hydroxide at night and sodium carbonate during the day(if i need more alk)
(Amazon food lye and BRS soda ash)
For calcium I dose Calcium chloride (BRS brand)

Previously I dosed Kalk, soda ash, and calcium chloride but found the evoperation restriction of saturated kalk to be annoying and sodium hydroxide takes up way less space In my cabnit.

So if you were my friend I would recommend you do not use Chris’ method and just dose as much Kalk as possible at night with no regards to alk.

I would instead recommend you first try to get outside air to your skimmer or use a co2 scrubber if you absolutely can’t run an air hose to outside air.
Then track your ph with an apex or something and switch to hydroxide dosing based off alk consumption.
Then when your average Ph gets to around 8.3 start skewing your dosing to the times your ph is lowest without causing a large alk swing.
Once you get to the point where your tank is consuming so much alk that your ph is getting above 8.5 start switching out some of your hydroxide dosing for sodium carbonate dosing (during the time your ph is highest).

I hope this helps

 

[Randy Holmes-Farley]

2. Chris seems to have come to some anecdotal conclusions that I have also; such as when you have good PH stability, instability of other parameters have less of a detrimental effect. When my ph stays above 8.25, alk swings, nutrient swings, etc. don't seem to affect my sensitive corals, but as soon as my PH drops to around 8.1 any instability throws them into stn/rtn.

If true, that may relate to the stability of bicarbonate concentration (or carbonate concentration) as opposed to pH or alk, since it's uptake is likely what corals actually care about. Alk in particular seems unlikely by itself to be important to a coral since it is a mathematical construct adding several things together in a specific way. It seems implausible that corals care exactly twice as much about carbonate as bicarbonate, for example (part of the math of total alkalinity).

A pH swing and an alk swing might be offset in ways that mitigate each other, but they more likely add to the instability of each other.

For example,

Higher pH usually happens during the light cycle. Higher pH is when bicarbonate concentration is lowest (for fixed alk). Alk demand also often follows the light cycle.

Assuming you dose alk 24/7 (or at night), then these two things (alk and pH swings) will pile on top of each other to minimize bicarbonate during the day (when they need it) and maximize it at night (when corals may not need it).

That sounds like exactly the wrong thing to do IF stability of bicarbonate is most important.

 

[Koigula]

All of these techniques are to mitigate a small water volume, a closed tight room with High CO2, and hopefully a high bioload.. I have 150 gallon tank and 150 gallon total sump and air exchanger.

This was discuss above but swings can be mitigated by water volume, reverse daylight refugium if big enough, air exchange and air through put venturi skimmer. This might be easier way with space. I have seem smaller pH swing running venturi 24/7 vs off at night.

I'll share results in a few weeks of alk and pH swings I have. I do not care for kH monitors though. I can test 1-2 times daily. Anecdotally I seem to do better with kalk and soda ash.

 

[Randy Holmes-Farley]

All of these techniques are to mitigate a small water volume, a closed tight room with High CO2, and hopefully a high bioload.. I have 150 gallon tank and 150 gallon total sump and air exchanger.

This was discuss above but swings can be mitigated by water volume, reverse daylight refugium if big enough, air exchange and air through put venturi skimmer. This might be easier way with space. I have seem smaller pH swing running venturi 24/7 vs off at night.

I'll share results in a few weeks of alk and pH swings I have. I do not care for kH monitors though. I can test 1-2 times daily. Anecdotally I seem to do better with kalk and soda ash.

Jus to quantify the effect though, a swing of "only'' 0.1 pH unit at pH 8.1 to 8.2 allows bicarbonate to vary by 7% and carbonate by 20%.

For bicarbonate, that's equivalent to an alk swing of 0.5 dKH.

 

[Koigula]

Here are results for last 24 hrs and sort of a best case example I can get. Air exchanger is a small unit running 10 min an hour in winter.

ph 8.37 high at 19:00, 8.33 low at 7:00; calibrated a month ago.
Alkalinity 148 ppm at 18:30, 143 at 7:30 am (Hanna triple rinse di, triple rinse tank water with 10 ml auto pippette)

Lights are 12:00 pm to 10:00 pm UV; 1:00 pm to 9:00 pm 4x ATI blue plus, 2 x Coral Plus
Saturated Kalk 10 pm to 12 pm, ~100 cc every 25 min
Refugium 8:00 pm to 11:00 am Kessil 360 ~70% output.
ESV 2 part - 8am 35 cc each - Bicarb/carb added near lowest point of alk swing cycle.

Seems like I should test at noon as well to see actual swing. Might a few times to see what I get.

Only true indicators of success I have are SPS budding tips and increase alk demand. Maybe that is all that matters. I do tests alk daily and nutrients weekly and calcium and magnesium closer to monthly. phosphates are 0.05 to 0.1 ppm and swing a bit I try to feed alot.

 

[Doctorgori]

I don‘t think you will get the exact method out of Chris because I don‘t think he fully understands what he’s doing chemically. I am not claiming I do either but on my quest for better PH I have spent a lot of time experimenting on my tank, reading @Randy Holmes-Farley posts, and have come to a few conclusions.

1. It does not matter what hydroxide you dose, they all provide the same ph boost per unit of alk.
Calcium hydroxide, sodium hydroxide, potassium hydroxide all provide the same. So Chris mixing hydroxides and keeping some secret doesn’t really make sense. Nor does using potassium hydroxide unless your tank uses a ton of potassium (mine does not).

according to randy
” The immediate effect on pH for dosing 1.4 dKH of each additive is about:
hydroxide 0.66 pH units (calcium or sodium, doesn't matter)
carbonate 0.34
bicarbonate -0.04 ”

2. Chris seems to have come to some anecdotal conclusions that I have also; such as when you have good PH stability, instability of other parameters have less of a detrimental effect. When my ph stays above 8.25, alk swings, nutrient swings, etc. don't seem to affect my sensitive corals, but as soon as my PH drops to around 8.1 any instability throws them into stn/rtn.

So dosing a hydroxide at night will give a greater alk swing than dosing over a 24 hour period but the 8.3 Ph stability may mitigate any detrimental effects of the alk swing.

With my tank I try to keep everything stable but put more care into keeping my PH at 8.3 +/- 1.5
I do keep a close eye on Alk, and don’t let it swing more than 1 dkh (but it usually doesn’t swing more than 0.5 daily)

I dose sodium hydroxide at night and sodium carbonate during the day(if i need more alk)
(Amazon food lye and BRS soda ash)
For calcium I dose Calcium chloride (BRS brand)

Previously I dosed Kalk, soda ash, and calcium chloride but found the evoperation restriction of saturated kalk to be annoying and sodium hydroxide takes up way less space In my cabnit.

So if you were my friend I would recommend you do not use Chris’ method and just dose as much Kalk as possible at night with no regards to alk.

I would instead recommend you first try to get outside air to your skimmer or use a co2 scrubber if you absolutely can’t run an air hose to outside air.
Then track your ph with an apex or something and switch to hydroxide dosing based off alk consumption.
Then when your average Ph gets to around 8.3 start skewing your dosing to the times your ph is lowest without causing a large alk swing.
Once you get to the point where your tank is consuming so much alk that your ph is getting above 8.5 start switching out some of your hydroxide dosing for sodium carbonate dosing (during the time your ph is highest).

I hope this helps

I read this a couple time as my sight is horrible…anyway not challenging anything whatsoever, but you can manage a 1dkh swing without nasty polyp bailout?
…again, hardly disputing your experience its just any alk swings like that for me are a disaster…

 

[reef_ranch]

I read this a couple time as my sight is horrible…anyway not challenging anything whatsoever, but you can manage a 1dkh swing without nasty polyp bailout?
…again, hardly disputing your experience its just any alk swings like that for me are a disaster…

I went from 8.5 to 9.7 after my first night dosing kalk in a full day’s evaporation dose. To say I was panicked is an understatement. But none of my SPS missed a beat! From big colonies to newly acquired frags, they maintained full color and polyp extension. My pH went from 8.0 to 8.3 .

 

[Doctorgori]

I went from 8.5 to 9.7 after my first night dosing kalk in a full day’s evaporation dose. To say I was panicked is an understatement. But none of my SPS missed a beat! From big colonies to newly acquired frags, they maintained full color and polyp extension. My pH went from 8.0 to 8.3 .

I’ve trolled the boards and there is no doubt alkalinity swings as a suspect in coral death is real. I suppose part of the gist here is perhaps maybe there are “ resistance” lowering parameters, pH swings….
the ole “stability argument while valid may not apply universally to all things at all times… carry on …. no one dare add a maximum tolerable alkalinity limit? ….online reputations are too valuable anymore I suppose …he he .3 scares me honestly

 

[fushi]

If true, that may relate to the stability of bicarbonate concentration (or carbonate concentration) as opposed to pH or alk, since it's uptake is likely what corals actually care about. Alk in particular seems unlikely by itself to be important to a coral since it is a mathematical construct adding several things together in a specific way. It seems implausible that corals care exactly twice as much about carbonate as bicarbonate, for example (part of the math of total alkalinity).

A pH swing and an alk swing might be offset in ways that mitigate each other, but they more likely add to the instability of each other.

For example,

Higher pH usually happens during the light cycle. Higher pH is when bicarbonate concentration is lowest (for fixed alk). Alk demand also often follows the light cycle.

Assuming you dose alk 24/7 (or at night), then these two things (alk and pH swings) will pile on top of each other to minimize bicarbonate during the day (when they need it) and maximize it at night (when corals may not need it).

That sounds like exactly the wrong thing to do IF stability of bicarbonate is most important.

This is interesting but getting past my understanding of alk. Do you have a thread explaining alkalinity and how it is calculated?

 

[reef_ranch]

I’ve trolled the boards and there is no doubt alkalinity swings as a suspect in coral death is real. I suppose part of the gist here is perhaps maybe there are “ resistance” lowering parameters, pH swings….
the ole “stability argument while valid may not apply universally to all things at all times… carry on …. no one dare add a maximum tolerable alkalinity limit? ….online reputations are too valuable anymore I suppose …he he .3 scares me honestly

I don’t doubt that Alk swings are a cause of coral deaths and I avoid them as much as possible. Maybe there’s something to the notion that in a high pH environment (higher in my case) an increase in Alk is not a death sentence?? I’m not smart enough to figure it out…

 

[ReefHunter006]

Jus to quantify the effect though, a swing of "only'' 0.1 pH unit at pH 8.1 to 8.2 allows bicarbonate to vary by 7% and carbonate by 20%.

For bicarbonate, that's equivalent to an alk swing of 0.5 dKH.

Does that swing get smaller at higher ph levels? Such as 8.4 to 8.3 or does it stay the same?

 

[Randy Holmes-Farley]

This is interesting but getting past my understanding of alk. Do you have a thread explaining alkalinity and how it is calculated?

Sure:

Chemistry and the Aquarium: What is Alkalinity?

Randy provides an overview of alkalinity as to why it's important, how it's measured, and how can it be tested.

reefs.com

Chemical Nature of Alkalinity
Based on the definition of total alkalinity given above, it is clear that anything that absorbs protons when the pH is dropped from normal levels to about 4-5 will be counted toward alkalinity. In seawater there are a variety of things that contribute, and in reef tanks the list is even longer. Equation 3 is the defining equation for total alkalinity in normal seawater.

TA = [HCO3–] + 2[CO3—] + [B(OH)4–] + [OH–] + [Si(OH)3O–] + [MgOH+] + [HPO4—] + 2[PO4—] – [H+]

The reason for the 2 in front of the carbonate and phosphate concentrations is that they take up two protons as the pH is dropped down to pH 4. All of the other ions just take up a single proton (except protons themselves which must be subtracted).

The main chemical species that contribute to alkalinity in seawater (and the reason it is useful to reefkeepers) are bicarbonate and carbonate (equations 1 and 2). The table below (from “Chemical Oceanography” by Frank Millero; 1996) shows the contribution to alkalinity from the major contributors in seawater at pH 8. If you start at higher pH, the relative contribution of bicarbonate will go down relative the others.

 

[fushi]

I read this a couple time as my sight is horrible…anyway not challenging anything whatsoever, but you can manage a 1dkh swing without nasty polyp bailout?
…again, hardly disputing your experience its just any alk swings like that for me are a disaster…

Yes when my PH had a daily swing between 8.25 - 8.45 my alk went from 7.3dkh to 8.5dkh and everything was fine and happy.

However a few weeks later my co2 media was about used up and my ph was slowly dropping to around 8.15 - 8.35 for a couple days, I stupidly took the scrubber off before I went to work and planed on changing it when I got home, I figured it wouldnt drop that much but it did, it dropped to 8.03 during the day and i got rtn on some tenuis frags, seeing this I promply put the scrubber back on and got my ph back up to 8.25 - 8.45 by the next day and things stopped rtn, some frags didn't make it an but others started healing over weeks later.

I was using sodium carbonate 2 part and kalk when all that went on, I have since switched to sodium hydroxide 2 part with a little extra sodium carbonate (so my ph doesn't go above 8.5). Currently my alk swing .5dkh daily due to me skewing my dosing to the night and things seem to be doing well.

 

[ReefHunter006]

Are there two part alternatives to kalk that can be used in similiar methods to prevent a Ph low by just dosing at night? I don’t feel like you could do that with traditional 2part.

 

[Randy Holmes-Farley]

Are there two part alternatives to kalk that can be used in similiar methods to prevent a Ph low by just dosing at night? I don’t feel like you could do that with traditional 2part.

Yes, there are many carbonate based two parts, and you can make my DIY recipes with hydroxide which can exactly match the pH effects of kalkwasser without drawbacks of evaporation limitations:

Second New DIY Two Part Recipe with Higher pH Boost

In a previous thread, I posted a true two part DIY recipe: https://www.reef2reef.com/threads/new-diy-two-part-recipes-with-higher-ph-boost.344500/ But some folks may want to just swap the new ingredient into my 2/3 part recipe (as used by BRS, for example). Here's the original recipe link...

www.reef2reef.com

New DIY Two Part Recipes with Higher pH Boost

Here's a first crack at what may end up being multiple possible recipes for a DIY two part that either has a higher pH or can be made more concentrated than traditional two part recipes. This one has about twice the pH raising effect compared to a carbonate based two part, per unit of...

www.reef2reef.com

 

[fushi]

Sure:

Chemistry and the Aquarium: What is Alkalinity?

Randy provides an overview of alkalinity as to why it's important, how it's measured, and how can it be tested.

reefs.com

Chemical Nature of Alkalinity
Based on the definition of total alkalinity given above, it is clear that anything that absorbs protons when the pH is dropped from normal levels to about 4-5 will be counted toward alkalinity. In seawater there are a variety of things that contribute, and in reef tanks the list is even longer. Equation 3 is the defining equation for total alkalinity in normal seawater.

TA = [HCO3–] + 2[CO3—] + [B(OH)4–] + [OH–] + [Si(OH)3O–] + [MgOH+] + [HPO4—] + 2[PO4—] – [H+]

The reason for the 2 in front of the carbonate and phosphate concentrations is that they take up two protons as the pH is dropped down to pH 4. All of the other ions just take up a single proton (except protons themselves which must be subtracted).

The main chemical species that contribute to alkalinity in seawater (and the reason it is useful to reefkeepers) are bicarbonate and carbonate (equations 1 and 2). The table below (from “Chemical Oceanography” by Frank Millero; 1996) shows the contribution to alkalinity from the major contributors in seawater at pH 8. If you start at higher pH, the relative contribution of bicarbonate will go down relative the others.

Thank You.
I'm going to have to read that article a few times.

On a similar side note, could you explain how hydroxides break down (if thats the correct term).
For example I understand that sodium carbonate (or bicarb.) react with calcium chloride to make sodium cloride and carbonate (or bicarb.) increasing total alk.
Does calcium hydroxide break into calcium and OH- ions? If so the addition of OH- ions probably would not be the ideal way to increase total alkalinity in a reef when corals need carbonate/bicarbonate to calcify? Or to make it more complicated do the OH- ions react with CO2 to make bicarbonate?

 

[ReefHunter006]

Yes, there are many carbonate based two parts, and you can make my DIY recipes with hydroxide which can exactly match the pH effects of kalkwasser without drawbacks of evaporation limitations:

Second New DIY Two Part Recipe with Higher pH Boost

In a previous thread, I posted a true two part DIY recipe: https://www.reef2reef.com/threads/new-diy-two-part-recipes-with-higher-ph-boost.344500/ But some folks may want to just swap the new ingredient into my 2/3 part recipe (as used by BRS, for example). Here's the original recipe link...

www.reef2reef.com

New DIY Two Part Recipes with Higher pH Boost

Here's a first crack at what may end up being multiple possible recipes for a DIY two part that either has a higher pH or can be made more concentrated than traditional two part recipes. This one has about twice the pH raising effect compared to a carbonate based two part, per unit of...

www.reef2reef.com

I would like to make sure I completely understand before I try this.

I started with Kalk slurry and dosed via PH rules (ph<8.33 then on) on APEX. I adjusted esv 2 part to keep alk swings under .5

So you believe the alternative two parts could be dosed solely based on PH need and not overshoot alk?