Double checking full EI dosing as per calc

[plantnoobdude]

Guys, I don't want to disturb your - obviously dedicated - EI party, however there are also different worlds around.
Firstly, dosing 30 ppm NO3 is insane in itself. But IF I ever had that much nitrate in my tank (and no ammonia), I would dose 4.7 ppm K, 14.7 ppm Mg, and 48.5 ppm Ca. There's way too much potassium there. I don't know what CO2 injection can do, but I'd expect a serious case of Mg and Ca deficiency. Plants prefer potassium to magnesium and calcium because in natural waters, potassium is usually in short supply.

Your theoretical K level is aligned with marschner in Terms of N:K, coincidence?

 

[_Maq_]

Your theoretical K level is aligned with marschner in Terms of N:K, coincidence?

It's Marschner, indeed. But not for Mg and Ca, they must be in much higher supply than what would apply if only consumption were taken into account.

 

[Wookii]

A debunked belief? I still believe water with low KH is prone to pH volatility. Well, "believe" is not the correct word. I just experience it routinely. Is there anything I'm missing here?

Yes Marcel, you’re missing the point that that pH fluctuations don’t matter.

 

[Yugang]

I'd expect a serious case of Mg and Ca deficiency

It's Marschner, indeed. But not for Mg and Ca, they must be in much higher supply than what would apply if only consumption were taken into account.

I would dose 4.7 ppm K, 14.7 ppm Mg, and 48.5 ppm Ca.

I have been chasing these ratios for years in my own tank, but was unable to find evidence that Ca really matters, and certainly not as a 3-4 multiple of the Mg as is often recommended in the hobby. We also had a thread on this subject Latest insights on Calcium and the conclusion on this forum was that just a tiny amount of Ca is sufficient for plants. Ca is mostly needed for the lifestock, that's why we add it in sufficient amounts

Do you have any references (experiments, science literature) to understand why we would need these high Ca ppm's?

With the forums that we have, 2 decades of postings by real experts and self proclaimed experts, we have many theories how to run tanks. I read a lot, but find it very challenging to know what is real and what are merely myths in our hobby's echo chamber. This is why I copy practices from successful tank keepers, and have learned that there are many competing truths in the hobby.

 

[_Maq_]

Yes Marcel

I'm not Marcel. I think I know who you mean, I know him personally, but it's not me.

 

[GreggZ]

A debunked belief? I still believe water with low KH is prone to pH volatility. Well, "believe" is not the correct word. I just experience it routinely. Is there anything I'm missing here?

Many if not most of the best planted tanks in the hobby run very, very little to no dKH. I've been running my tank for years at zero dKH for years now.

The pH is very stable other than when I drop it via CO2 injection. If tanks experience a pH crash it's almost always related to poor maintenance.

Here's a good article about low pH tanks. My tank is pictured there when I was running 1 dKH.

2hr Aquarist Low pH Tanks

But if you are a disciple of Marcel's then I am guessing there is little we will agree on and I am pretty sure I know where this is going. It almost always ends the same way.

 

[Yugang]

I'd like to think we are a "broad church",

But if you are a disciple

Not sure where this is heading

 

[Hanuman]

Guys, I don't want to disturb your - obviously dedicated - EI party, however there are also different worlds around.

Fist of all that sounds ironic. Second of all there is no party here nor are we promoting any EI regime. We are merely commenting on some technical feature on the calculator that should either stay or go. Granted it's starting to go off topic.

Firstly, dosing 30 ppm NO3 is insane in itself. But IF I ever had that much nitrate in my tank (and no ammonia), I would dose 4.7 ppm K, 14.7 ppm Mg, and 48.5 ppm Ca. There's way too much potassium there. I don't know what CO2 injection can do, but I'd expect a serious case of Mg and Ca deficiency. Plants prefer potassium to magnesium and calcium because in natural waters, potassium is usually in short supply.

It's not, even if that sounds monstrous to you. Here , this is what I am dosing and my tank is running smoothly with no hiccups. No Algea, co PH crush no shenanigans of any sort even with dKH close to 0 or at 0.

A debunked belief? I still believe water with low KH is prone to pH volatility. Well, "believe" is not the correct word. I just experience it routinely. Is there anything I'm missing here?

Not sure what you are doing, but I have been using RO water for the past 2 years and never have I experienced a crash and so has anyone I know using RO water and not adding any carbonates to the tank. Maybe if you are running a bare tank with no substrate and basically no hardscape, perhaps that would happen. If you are experiencing those crashes then you should be experiencing them daily pretty violently and your fish would probably be dead by now.

Your theoretical K level is aligned with marschner in Terms of N:K, coincidence?

It's Marschner, indeed. But not for Mg and Ca, they must be in much higher supply than what would apply if only consumption were taken into account.

This seems to be taking yet another unnecessary road turn. Perhaps we should keep in line with the OP?

 

[Wookii]

I'm not Marcel. I think I know who you mean, I know him personally, but it's not me.

😂

 

[GhostVoice]

It would be easy for admin to check the exact location of Marcel vs Maq based on IP. Marcel lives in Lysa nad Labem, Maq does not. Marcel and Maq were working together on some experiments. They were collegues. Marcel then quit the aquarium hobby, Maq does not and continued to do other experiments by himself. I think Maq is much smarter than Marcel, and he definitely is not his disciple. Marcel was the one who learned from Maq. That's just for clarification.

 

[_Maq_]

I'd like to clarify that I run most of my tanks with near zero alkalinity.
The original statement was this:

I suspect that it’s a hang over from the now debunked belief that low KH could lead to pH crashes.

It says nothing on whether pH moves are dangerous or not, it simply states that low KH does not lead to pH crashes. To that, I said that pH is indeed volatile. Nothing more.

 

[_Maq_]

I have been chasing these ratios for years in my own tank, but was unable to find evidence that Ca really matters, and certainly not as a 3-4 multiple of the Mg as is often recommended in the hobby. We also had a thread on this subject Latest insights on Calcium and the conclusion on this forum was that just a tiny amount of Ca is sufficient for plants. Ca is mostly needed for the lifestock, that's why we add it in sufficient amounts
Do you have any references (experiments, science literature) to understand why we would need these high Ca ppm's?

I'm not very concerned about Mg : Ca ratio. It seems that plants tolerate quite wide fluctuations without much harm. What I care for is the ratio between potassium (and ammonia) and Ca, Mg. Below are some quotations from Fageria - The Use of Nutrients in Crop Plants [2009]:

 

[Yugang]

I'm not very concerned about Mg : Ca ratio. It seems that plants tolerate quite wide fluctuations without much harm. What I care for is the ratio between potassium (and ammonia) and Ca, Mg. Below are some quotations from Fageria - The Use of Nutrients in Crop Plants [2009]:

I would dose .... 48.5 ppm Ca

For aquatic plants, could you refer to any experiment or science that indicate that we need more than a few ppm Ca? Otherwise, is it fair to say that this recommendation is a personal opinion (which is fine, as I also have opinions)?

I'd expect a serious case of Mg and Ca deficiency.

Have you experienced Ca deficiency in any of your tanks? In our thread Latest insights on Calcium no one on this forum raised warning here. We should care about shrimp, but that's another discussion.

My suspicion, after worrying about Ca for several years, scanning forums for wisdom, is that the far majority of statements on Ca deficiencies and Ca target ppm's are most likely not more than personal opinions and not based on relevant observations in aquatic plants.

As I do not want to derail this thread, may I suggest that you add further insights to the thread Latest insights on Calcium ?

 

[Yugang]

It is, as you approach pure H2O pH becomes <"more and more unstable">, due to the ratio (and log10) nature of the pH scale.

@dw1305 you know 1000 times more about chemistry than I, and I do not want to be the wisenose ...

What you write about the logarithmic relationship is true, this holds when the water has sufficiently high buffering capacity, for example KH>1.
What I am reading is that with KH approaching 0 the HCO3/CO2 buffering capacity is insufficient and the log relationship between pH and CO2 concentration breaks down leading to potentially a crash.

 

[JoshP12]

The Saga continues …. What about substrate?!

 

[JoshP12]

Herein lies the problem. What we say on the web lives forever.

I have said this many times over the years.

Whatever I said I believed to be true at the time I said it.

And I know Tom Barr would say the same thing.

I’ve changed my view in the middle of a post 😂 … as I think through a problem.

 

[dw1305]

Hi all,

@dw1305 you know 1000 times more about chemistry than

I wish, I'm not a chemist and I had to get people to explain pH and buffering <"in terms I could understand"> before I could apply them to the real world situations.

The easiest way to think about it is the Brønsted-Lowry definition of acids <"that acids are proton (H+) donors and bases are proton acceptors"> and what matter is the amount of them in solution, not their ratio. It is the ratio, which when, expressed on the log10 scale, that we measure as pH ("the negative log of the H+ activity")

What you write about the logarithmic relationship is true, this holds when the water has sufficiently high buffering capacity, for example KH>1.

The relationship remains logarithmic, but when we are at pH7 we have equal numbers (equal activity really) of H+ and OH- ions from the deprotonation (<"self ionization of water">). We actually have an OH- and a hydronium ion (H3O+), but that doesn't make any practical difference. Via Wikipedia:

.......... Water molecules dissociate into equal amounts of H3O+ and OH−, so their concentrations are almost exactly 1.00×10−7 mol dm−3 at 25 °C and 0.1 MPa. A solution in which the H3O+ and OH− concentrations equal each other is considered a neutral solution. ......... Pure water is neutral, but most water samples contain impurities. If an impurity is an acid or base, this will affect the concentrations of hydronium ion and hydroxide ion. Water samples that are exposed to air will absorb some carbon dioxide to form carbonic acid (H2CO3) and the concentration of H3O+ will increase due to the reaction H2CO3 + H2O = HCO3− + H3O+. The concentration of OH− will decrease in such a way that the product [H3O+][OH−] remains constant for fixed temperature and pressure. Thus these water samples will be slightly acidic. If a pH of exactly 7.0 is required, it must be maintained with an appropriate buffer solution.........

What I am reading is that with KH approaching 0 the HCO3/CO2 buffering capacity is insufficient and the log relationship between pH and CO2 concentration breaks down leading to potentially a crash.

If you don't have any carbonate buffering (dKH) the dissolved CO2 (the small amount that becomes H2CO3) <"will lower the pH">, but as soon as you have enough dKH to neutralise that acid the pH will go to ~pH8, the <"pH ~ HCO3- ~ CO2 equilibrium point at 420 ppm atmospheric CO2">. When you don't have any buffering then pH is just a movable feast, but the changes in ionic concentration are really small and that is what matters.

cheers Darrel

 

[Yugang]

When you don't have any buffering then pH is just a movable feast, but the changes in ionic concentration are really small and that is what matters.

This is very helpful, and if I understand you correctly there is no reason to worry when KH approaches 0.

I was triggered by a post from Tom Barr, #2, who mostly talks from a sound scientific understanding as well as practical experience
"Well no, you will not be able to determine at a KH of 0. pH test probes will also not work on pure water. You have some salts but no HCO3. HCO3/CO2 is an acid base buffered system. Without the base, there's no pH/KH relationship. The system will crash, it might not have done this yet for you, but you'll get burned at some point. And have dead fish."

It is an old post, perhaps Tom didn't have his PhD yet

 

[dw1305]

Hi all,

and if I understand you correctly there is no reason to worry when KH approaches 0.

Yes and no unfortunately, it is back to the <"unknown unknowns"> and freshwater being both:

• <"Very variable in its chemical composition">, and
• a very efficient <"amphoteric solvent">.

So now we are really at <"horses for courses">, and fish (and plants) adapted to hard water aren't going to have the physiological adaptations to survive in very soft water. Some people will argue that <"fish will adapt to the situation they are placed in">, but I don't subscribe to that view. Personally I use fish (and plants) that naturally occur in <"water with similar chemistry"> to that which I can provide.

Because water is a very efficient solvent soft water will always be "tannin stained" with humic substances and <"it is these substances"> that provide the <"buffering system in very soft water">*. If you placed most fish into DI water? Osmotic effects are going to do for them fairly quickly as they lose salts to the surrounding water and can't replace them.

*Morris, C., Val, A.L., Brauner, C.J. and Wood, C.M., 2021. The physiology of fish in acidic waters rich in dissolved organic carbon, with specific reference to the Amazon basin: ionoregulation, acid–base regulation, ammonia excretion, and metal toxicity. Journal of Experimental Zoology Part A: Ecological and Integrative Physiology, 335(9-10), pp.843-863.

was triggered by a post from Tom Barr, #2, who mostly talks from a sound scientific understanding as well as practical experience
"Well no, you will not be able to determine at a KH of 0. pH test probes will also not work on pure water. You have some salts but no HCO3. HCO3/CO2 is an acid base buffered system. Without the base, there's no pH/KH relationship. The system will crash, it might not have done this yet for you, but you'll get burned at some point. And have dead fish."

Tom (@plantbrain ) is <"right about pH meters">, after that I'm guessing that this really relates to water without any humic substances. This isn't a criticism of Tom, just a reflection that he comes from <"a very different place"> as a scientist, a place where ecology (and shades of grey) aren't really relevant.

cheers Darrel

 

[Yugang]

Hi all,

Yes and no unfortunately, it is back to the <"unknown unknowns"> and freshwater being both:

• <"Very variable in its chemical composition">, and
• a very efficient <"amphoteric solvent">.

So now we are really at <"horses for courses">, and fish (and plants) adapted to hard water aren't going to have the physiological adaptations to survive in very soft water. Some people will argue that <"fish will adapt to the situation they are placed in">, but I don't subscribe to that view. Personally I use fish (and plants) that naturally occur in <"water with similar chemistry"> to that which I can provide.

Because water is a very efficient solvent soft water will always be "tannin stained" with humic substances and <"it is these substances"> that provide the <"buffering system in very soft water">*. If you placed most fish into DI water? Osmotic effects are going to do for them fairly quickly as they lose salts to the surrounding water and can't replace them.
*Morris, C., Val, A.L., Brauner, C.J. and Wood, C.M., 2021. The physiology of fish in acidic waters rich in dissolved organic carbon, with specific reference to the Amazon basin: ionoregulation, acid–base regulation, ammonia excretion, and metal toxicity. Journal of Experimental Zoology Part A: Ecological and Integrative Physiology, 335(9-10), pp.843-863.

Tom (@plantbrain ) is <"right about pH meters">, after that I'm guessing that this really relates to water without any humic substances. This isn't a criticism of Tom, just a reflection that he comes from <"a very different place"> as a scientist, a place where ecology (and shades of grey) aren't really relevant.

cheers Darrel

Thank you so much Darrel, and apologies for causing you so much trouble.

I believe it is fair to observe the reality that very few people are actually reporting on tragic incidents with KH =0 and CO2 injection. While we do not need to know the full science, do not controll all parameters, it seems not the biggest threat in real life.

A take away that I have from this discussion is that it can be quite tricky to use a pH controller when KH is really low. Some of our friends with really beautifull tanks and fish are doing this, perhaps not realising the risks involved. Now we may be lucky, as a pH that goes down (rather than up) will cause the controller to switch off.