# Kh and Nitrifying Bacteria



## rpadgett37

I understand the nitrogen cycle pretty well, but I've run into something that has me stumped. 

First the question: Is there a direct relationship between KH and the growth of Nitrifying Bacteria? 

Here's why I ask: I am cycling a tank at the moment with ammonia. I have followed the online instructions I found on the Betta site and have a starting point of 5ppm ammonia concentration in the water.

The starting water parameters are PH 7.9, KH 1dK and temp 78-80 degrees. 

I have seeded the tank with Bacteria, a couple of different products actually (Seachem Stability for 7 days, then Nutrafin Safe Start Plus on day 8). After 9 days, I am seeing no movement whatsoever either in ammonia or nitrite levels. I've used tests by API and Nutrafin each time I measure to be sure I am getting accurate measurements. The tank I cycled previously showed nitrites on day 3 after seeding the tank, and I am stumped as to why nothing is happening in this tank.

Someone suggested to me that low kH levels will inhibit nitrifying bacteria growth and function. I know that as PH values lessen, nitrifying bacteria growth and function slow and eventually stop altogether at around PH 6, and that there is a direct relationship between PH and KH. As my starting kH is so low, this comment piqued my interest. 

The only problem is I can find nothing on the internet that corroborates a relationship between kh and these bacteria. Only about PH. Now I know that nitrifying bacteria use (among other things) carbon in the water to do their thing, so does that mean if the carbon source in the water is either very limited or non existent, they stop working or fail to grow at all? 

There you have it. Your comments and experience are welcome.


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## sprmankalel

I don't know anything about your question here but I had a few myself. 
Do you have an already established tank? If so, I would suggest taking some media from there and put it into the new tank's filter and see what happens to the ammonia levels. Having one or more established tanks means infant cycling of new tanks.


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## rpadgett37

sprmankalel said:


> I don't know anything about your question here but I had a few myself.
> Do you have an already established tank? If so, I would suggest taking some media from there and put it into the new tank's filter and see what happens to the ammonia levels. Having one or more established tanks means infant cycling of new tanks.


Unfortunately, this is the first tank of 5. This will be the tank that seeds the others.


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## sprmankalel

Anyone that you can get media from?


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## rpadgett37

sprmankalel said:


> Anyone that you can get media from?


 Yes, but not anytime soon.


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## sprmankalel

I'd say let it be for a few days. As long as you have an ammonia source in the tank it should happen.
_Posted via Mobile Device_


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## RSVBiffer

Nitrifying bacteria are affected by pH rather than alkalinity. For a cycling tank though (or even a mature tank) your KH is too low as it will allow pH swings and cycling tends to drop the pH and you have nothing to buffer against it. I would suggest you raise it to somewhere around 4dKH (at the minimum). Your pH is fine at the moment but once the cycle kicks in you are going to be very prone to crashes.


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## rsskylight04

For buffer I would reccomend natural sources such as limestone, coral, or seashells rather than chemical sources like baking soda. Natural sources provide slow release longterm buffer while baking soda is fast acting and must be carefully measured and re dosed with each water change. Crushed coral is available at most pet shops and a can be put directly into the tank or in a mesh bag in your filter.


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## rpadgett37

Already have something standing by to fix the kH.

PH rather than Alkalinity? Not sure what you mean by that. Alkalinity is a part of PH, so what am I missing here?

Also still interested in why my cycle isn't going anywhere though it has good parameters.


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## beaslbob

I remember reading an old article that the forward aerobic bacteria cycle does in fact use up KH. Whether or not low KH affects the bacteria is another question.
And further that the reduction of the resuting nitrates through either plant or bacterial activity in fact returns that KH.

But that was an article from years ago.


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## rpadgett37

beaslbob said:


> I remember reading an old article that the forward aerobic bacteria cycle does in fact use up KH. Whether or not low KH affects the bacteria is another question.
> And further that the reduction of the resuting nitrates through either plant or bacterial activity in fact returns that KH.
> 
> But that was an article from years ago.


Interesting. There aren't any plants in there at the moment, so it sounds like to be sure, I will need to raise the Kh and see what happens.


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## beaslbob

rpadgett37 said:


> Interesting. There aren't any plants in there at the moment, so it sounds like to be sure, I will need to raise the Kh and see what happens.


 
The kH is also increased throu anoxic bacteria reducing nitrates in the substrate.

FWIW I have had pH values of over 8.4 in my planted tanks even with peat moss in the substrate.

And with the peat moss the kH is 4 degrees for at least 2 years. KH did rise on the tank I had just plain sand though.

Tanks were not circulated and the plant action IMHO made the tank a net consumer of carbon dioxide and producer of oxygen each 24 hours.

Just shooting in the dark here, if your kH is below 4 degrees I would just add some baking soda to get it up to 4 degrees.

And with a cycling tank the low pH and kH could just be part of the cycle. Once the cycle matures both will probably go up.

If you can, I would add plants even if you had to protect the plants with come kind of partition.

The plant action will consume ammonia directly preventing spikes until the bacteria builds up.

What I would recommend against is adding various things to correct pH problems or help the cycle with chemicals. Dechlors and ammonia locks can stall the cycle and degrade the environment. While adjusting the kH as above it safe, chasing pH is unwise and dangerous. IMHO.


my .02


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## rpadgett37

beaslbob said:


> The kH is also increased throu anoxic bacteria reducing nitrates in the substrate.
> 
> FWIW I have had pH values of over 8.4 in my planted tanks even with peat moss in the substrate.
> 
> And with the peat moss the kH is 4 degrees for at least 2 years. KH did rise on the tank I had just plain sand though.
> 
> Tanks were not circulated and the plant action IMHO made the tank a net consumer of carbon dioxide and producer of oxygen each 24 hours.
> 
> Just shooting in the dark here, if your kH is below 4 degrees I would just add some baking soda to get it up to 4 degrees.
> 
> And with a cycling tank the low pH and kH could just be part of the cycle. Once the cycle matures both will probably go up.
> 
> If you can, I would add plants even if you had to protect the plants with come kind of partition.
> 
> The plant action will consume ammonia directly preventing spikes until the bacteria builds up.
> 
> What I would recommend against is adding various things to correct pH problems or help the cycle with chemicals. Dechlors and ammonia locks can stall the cycle and degrade the environment. While adjusting the kH as above it safe, chasing pH is unwise and dangerous. IMHO.
> 
> 
> my .02


The only action I took was to empty the tank, use the same source water to refill it, raised the kh to around 4. I'm letting it sit till tomorrow morning where I'll check water parameters after 18 hours and add ammonia and bacteria once more. This is probably an extreme measure, but I really want to see what happens with keeping everything reasonably the same with a higher KH.

I know better than to chase the PH, and at the moment, the only parameter I am fiddling with is the KH, and that only a little. I wish I could add some plants at this point, but resources are exhausted for the month  And it is a bit early for the anoxic bacteria to be doing anything just yet, but it's good to know what effect they will have on the system once in place. There's always so much more to learn.


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## RSVBiffer

rpadgett37 said:


> Already have something standing by to fix the kH.
> 
> PH rather than Alkalinity? Not sure what you mean by that. Alkalinity is a part of PH, so what am I missing here?
> 
> Also still interested in why my cycle isn't going anywhere though it has good parameters.


Alkalinity is a measure of a systems ability to neutralise acid, i.e. 'soak up' hydrogen ions which would otherwise cause the pH to fall. Pure water has 0dKH, 0dGH but a pH of 7 rather than 1 as there are neither H- or OH-. The higher the alkalinity the higher the buffering capacity which means that to lower the pH we (usually) need to lower the alkalinity. Setups with a low KH but high pH value tend to be unstable and subject to pH crashes. The nett result of the nitrogen cycle is the production of H- ions which would decrease the pH but is counteracted by the buffering effect of the alkalinity. 

Regarding your cycle I would say (from your figures) you just need to give it time. It is possible that some factor is affecting it but it also has not been running that long. You give the starting pH etc values but not the current ones, have you checked these lately?


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## rpadgett37

Ok. I didn't say that very clearly. The PH is the measurement of the alkalinity, while the alkalinity of the water can impair both growth and function of the nitrifying bacteria. The lower the alkalinty, the more pronounced the effect. 

For my clarification, I was under the impression that the alkalinity itself had no buffering capacity, and that it is what needs buffering. I had thought carbonated hardness is what buffers the alkalinity, absorbing H- ions introduced into the water before it can interact with the alkalinity of the water. The higher the Kh measurement of the carbonates in the water, the more buffered alkalinity becomes at a given PH measurement, the less prone it is to fluctuations. Again, for my clarification. 

And yes I have. I measure the water daily for PH, KH, ammonia and nitrites. The daily results match the starting measurements.


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## RSVBiffer

pH isn't a measurement of the alkalinity. You have a KH of about 20ppm and a pH of 7.9, in my Amazon tank I have a of KH 60-70ppm but a pH of 6.8. There is a direct relationship between the two but other factors come into effect. A specific alkalinity value will give different pH readings in different tanks.

Carbonate hardness is another term for alkalinity.

I think you may be confusing the alkalinity, in terms of an aqueous solution's buffering capacity, with how the pH may be acidic or alkaline and has a' higher alkalinity'. I hope that makes sense. Of course, it shouldn't be alkali but base...at least it would simplify things ;-).


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## tanked

Not addressing the kh/cycle relation but possibly your ammonia is too high? Five ppm might be high for any cycle start and my understanding is twoish ppm when using bacteria starters is best? Also eighty degrees F is on the high end for those starters?
_Posted via Mobile Device_


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## RSVBiffer

I would say 5ppm is well within limits, Waterlife advise 5-10ppm before using Bacterlife. The pH is ideal for the Nitrosomonas and slightly high for optimum Nitrobacter growth but certainly nothing to worry about. The temp is ideal for optimum growth of both types of bacteria (77-86'F).


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## rpadgett37

RSVBiffer said:


> pH isn't a measurement of the alkalinity. You have a KH of about 20ppm and a pH of 7.9, in my Amazon tank I have a of KH 60-70ppm but a pH of 6.8. There is a direct relationship between the two but other factors come into effect. A specific alkalinity value will give different pH readings in different tanks.
> 
> Carbonate hardness is another term for alkalinity.
> 
> I think you may be confusing the alkalinity, in terms of an aqueous solution's buffering capacity, with how the pH may be acidic or alkaline and has a' higher alkalinity'. I hope that makes sense. Of course, it shouldn't be alkali but base...at least it would simplify things ;-).


Yes. I was confusing the two. Again for clarity, PH is a measurement of the total acidic and base compounds in the water? Also, then to say Carbonated Hardness and Alkalinity is saying the same thing, meaning the terms are interchangeable? 

If that is the case, then KH does have an impact on the growth and function of nitrifying bacteria (specifically Nitrosomanus). The lower the alkalinity of the water, the more impaired the Nitrosomanus becomes. Is that right? I am guessing that another way to say that is that the more acidic compounds in the water, the more this bacteria is impaired which is why people associate PH with this impairment rather than KH. Really beginning to zero in here. 

So if that is correct, then a tank can have the measurements you mentioned (60ppm Carbonated Hardness, PH 6.8) and these bacteria may not be as impaired as say 20ppm and PH 6.8. Hope that's clear.

Already started the restart and the starting value are PH 7.4 (came down from adding sodium bi-carbonate to the water), KH 3dk. Temp same. Ammonia concentration same.


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## beaslbob

rpadgett37 said:


> Yes. I was confusing the two. Again for clarity, PH is a measurement of the total acidic and base compounds in the water? Also, then to say Carbonated Hardness and Alkalinity is saying the same thing, meaning the terms are interchangeable?
> 
> If that is the case, then KH does have an impact on the growth and function of nitrifying bacteria (specifically Nitrosomanus). The lower the alkalinity of the water, the more impaired the Nitrosomanus becomes. Is that right? I am guessing that another way to say that is that the more acidic compounds in the water, the more this bacteria is impaired which is why people associate PH with this impairment rather than KH. Really beginning to zero in here.
> 
> So if that is correct, then a tank can have the measurements you mentioned (60ppm Carbonated Hardness, PH 6.8) and these bacteria may not be as impaired as say 20ppm and PH 6.8. Hope that's clear.
> 
> Already started the restart and the starting value are PH 7.4 (came down from adding sodium bi-carbonate to the water), KH 3dk. Temp same. Ammonia concentration same.


from what i understand carbonate hardness is the carbonate in the system. alk is the resistance to ph changes. So technically they are not precisely the same. But practically, allmost all the resistance to ph change does in fact come from the carbonate ion. So alk is used as a substitute for carbonate because it is much easier to measure.

pH is a function of carbonate, and carbon dioxide (plus the obvious h+ ions and the like).

What I do with my systems is heavily plant them right from the start. This reduces carbon dioxide and consumes ammonia directly. Which prevents the forward aerobic bacteria spikes. Which in turn reduces the h+ ions released which consume alk also.

Plus the reduced carbon dioxide increases the pH.

So after a few weeks the bacteria consume more and more ammonia then nitrItes resulting in nitrates. Which does reduce carbonate but at a much slower rate. 

At that point the plants start consuming nitrates which returns the carbonate used up by the aerobic bacteria cycle.

So I wind up with low carbon dioxide and carbonate being returned to the system.

As a result I have a high pH (8.4+), KH of 4 degrees. and all fish including those requiring soft water thrive.

But that's just my .02


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## RSVBiffer

As far as I am aware the factors affecting the growth of the nitrifying bacteria are temperature, pH, nutrients, oxygen, trace elements, light, toxins and salinity and alkalinity (carbonate hardness) has no direct bearing but is a factor in maintaining a 'steady' pH. The alkalinity will be reduced in a cycling tank.

The image below shows how alkalinity and pH are affected during a cycle


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## beaslbob

RSVBiffer said:


> As far as I am aware the factors affecting the growth of the nitrifying bacteria are temperature, pH, nutrients, oxygen, trace elements, light, toxins and salinity and alkalinity (carbonate hardness) has no direct bearing but is a factor in maintaining a 'steady' pH. The alkalinity will be reduced in a cycling tank.
> 
> The image below shows how alkalinity and pH are affected during a cycle


FWIW what I emphasize is a stable pH. Which is not necessarily a steady pH.

Stability is the reaction of a system when deviated from some steady state. (that is a balanced state).

It is entirly possible to have a very stable large daily pH swing and a very unstable steady pH.

I have just found that stable conditions are much easier to maintain and require tons and tons less effort plus being much more error prone.

my .02


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## corina savin

What is the Kh of the tap water?
Here is my experience with Kh during cycle: my tap water Kh is close to 7. I also notice going down while the tank was cycling. I even asked this question on a different forum. I received several answers: peat in the substrate and use by algae. Without a source of CO2 (fish or plants), algae will consume carbonates as a source of carbon. I can guess that bacteria will do the same. If your tap water has some Kh, a water change will replace it. Baking soda is another short term solution. My tank eventually cycled


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## beaslbob

lowering pH and kH is normal during the aerobic bacteria cycle and the result of that bacterial action.

As the resultant nitrates are consumed (through plants or anaerobic/anoxic bacteria) both recover.

Plants can and will use carbonate instead of co2.

But the above is void of plants.

Plants will slow or eliminate the pH and kH drops in cycleing tanks and return carbonate as they consume the resultant nitrates.

Still as you said it is possibe co2 starved plants will in fact lower the carbonate.


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## rpadgett37

This is all really informative, and perhaps I am trying to oversimplify something that is very complex. 

But in a new tank, with only water and ammonia with seeded bacteria, I am trying to understand why the bacteria is failing to thrive in an environment that is conducive to their growth by measurable standards. Something is inhibiting the growth of the nitrifying bacteria and I am trying to understand what that could be. What is happening is calling into question the things I had thought before, as well as the instructions on how to do an ammonia cycle altogether.


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## beaslbob

I would check the ammonia with the multi test ammonia kit to see if it is all locked up.

Other then that I would stop dosing ammonia and let the tank cycle.

If needed add ammonia to maintain it at a lower level like 1 ppm or so.

but what I would really do of course is add plants like anacharis.

my .02


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## rpadgett37

beaslbob said:


> I would check the ammonia with the multi test ammonia kit to see if it is all locked up.
> 
> Other then that I would stop dosing ammonia and let the tank cycle.
> 
> If needed add ammonia to maintain it at a lower level like 1 ppm or so.
> 
> but what I would really do of course is add plants like anacharis.
> 
> my .02


NP. When you say ammonia locked up, what do you mean.


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## beaslbob

rpadgett37 said:


> NP. When you say ammonia locked up, what do you mean.


prime and other chemicals work by changing ammonia from the dangerous free form to the locked form. One is actually ammonium or something like that.

the multitest kit measures the danger free ammonia as well was the total of the locked and free forms. FWIW the ammonia dots you put in your tank measure only the free form.

But api and most ammonia test kits only measure the total of the locked and free.

So I guess if your amonia is locked up stop dosing until it goes down. Just like if there was fish in the tank.

Of course you may just want to reduce dosing levels at any rate anyway.

my .02 and just a suggestion.


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## rpadgett37

beaslbob said:


> prime and other chemicals work by changing ammonia from the dangerous free form to the locked form. One is actually ammonium or something like that.
> 
> the multitest kit measures the danger free ammonia as well was the total of the locked and free forms. FWIW the ammonia dots you put in your tank measure only the free form.
> 
> But api and most ammonia test kits only measure the total of the locked and free.
> 
> So I guess if your amonia is locked up stop dosing until it goes down. Just like if there was fish in the tank.
> 
> Of course you may just want to reduce dosing levels at any rate anyway.
> 
> my .02 and just a suggestion.


I stopped doing when it reached the desired concentration. And I have a test already that measures the ammonium and locked ammonia, much to my surprise.

So I am going to take a little of everything I've read and doing it a little differently. First, I raised the KH. Second, I am seeding the tank as directed and will raise the ammonia levels slowly, over a period of days until I hit 3-4ppm. Hold it till nitrites show up, let it from to .5ppm and hold it there till the cycle completes. Finally, just went and bought 2 bunches of Anacharis that I will put into the tank.

Thanks for all the info and advice. I will probably return to some of the other items mentioned in here as they interest me as well.


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## corina savin

I would also increase the temperature and add aeration. Bacteria needs oxygen as well.
Kh ( spelled Karbonate as in german language) is the same as Carbonate Hardness. Some people call it alkalinity but it has nothing to do with the alkaline pH (which is what we call pH above 7). Don't be confused by this terms. Kh=carbonate hardness=alkalinity.


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## rpadgett37

corina savin said:


> I would also increase the temperature and add aeration. Bacteria needs oxygen as well.
> Kh ( spelled Karbonate as in german language) is the same as Carbonate Hardness. Some people call it alkalinity but it has nothing to do with the alkaline pH (which is what we call pH above 7). Don't be confused by this terms. Kh=carbonate hardness=alkalinity.


I've been educated on that point. And check mark on the rest. Thank you.


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## beaslbob

rpadgett37 said:


> I stopped doing when it reached the desired concentration. And I have a test already that measures the ammonium and locked ammonia, much to my surprise.
> 
> So I am going to take a little of everything I've read and doing it a little differently. First, I raised the KH. Second, I am seeding the tank as directed and will raise the ammonia levels slowly, over a period of days until I hit 3-4ppm. Hold it till nitrites show up, let it from to .5ppm and hold it there till the cycle completes. Finally, just went and *bought 2 bunches of Anacharis that I will put into the tank*.
> 
> Thanks for all the info and advice. I will probably return to some of the other items mentioned in here as they interest me as well.


you may be surprised at what happens after you add the anacharis.


my .02


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## rpadgett37

beaslbob said:


> you may be surprised at what happens after you add the anacharis.
> 
> 
> my .02


The only thing about the anacharis is I don't want it to do the job of the nitrifying bacteria I am trying to grow. I don't plan to keep these plants in this tank so when I take them out, I am concerned there will be a shortage of the bacteria i need to cycle the tank.I will be adding other plants, but they will all be anubias variaties.

I'm not that familiar with a silent cycle (which this approximates) so I don't know the effect of the fast growing plants in the cycle.


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## beaslbob

rpadgett37 said:


> The only thing about the anacharis is I don't want it to do the job of the nitrifying bacteria I am trying to grow. I don't plan to keep these plants in this tank so when I take them out, I am concerned there will be a shortage of the bacteria i need to cycle the tank.I will be adding other plants, but they will all be anubias variaties.
> 
> I'm not that familiar with a silent cycle (which this approximates) so I don't know the effect of the fast growing plants in the cycle.


 
The lack of bacteria is not a concern with planted tanks.

What the plants do is first consume ammonia if present.

But the bacteria are still there and will still consime ammoonia.

With the plants providing a higher oxygen (and lower co2) each 24 hour period the bacteria will still reproduce and expand.

As the bacteria expands less and less ammonia is available for the plants which will eventually start using the resulting nitrates for nitrogen.

So you can get little to no ammonia spikes or a silent cycle in the process.

By limiting the bioload (adding fish slowly) what you will see is at most an initial nitrate spike (20-30 ppm) which will drop down after a few weeks.

Sometimes you can get a nitrIte spike but usually even that is very short lived. Like a day or two.

Again that is what I see if you add the fish slowly. And not adding food the first week or so. By dosing large ammmonia you could possibly see longer lasting spikes.

my .,02


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## rpadgett37

A follow up question. I am not the only person to run into this problem with the nitrifying bacteria not settling in despite having been seeded. There are others in a different forum who have had tanks that wouldn't cycle even after one or two months. 

So since there is no direct connection between KH and nitrifying bacteria, then the question now is what can I (we) do to provide the environment most condusive to bacterial growth and function in a brand new, non planted aquarium, fish out, first time cycle aquarium? 

PH and Temp are known. Kh, Gh, CO2 and O2 are factors but how much and in what proportions I do not know. Salinity is a black hole as is alkalinity versus Carbonated Hardness. 

Shot in the dark but if KH and GH are low, increase them (I bumped my kH to around 70ppm (3.8dk) and my gh from 20-30ppm (about 1 dk) to 80 ppm (around 4.5 to 5 dH)? 

Aeration? 

Really guesses on my part, so any thoughts are much appreciated.


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## rpadgett37

beaslbob said:


> The lack of bacteria is not a concern with planted tanks.
> 
> What the plants do is first consume ammonia if present.
> 
> But the bacteria are still there and will still consime ammoonia.
> 
> With the plants providing a higher oxygen (and lower co2) each 24 hour period the bacteria will still reproduce and expand.
> 
> As the bacteria expands less and less ammonia is available for the plants which will eventually start using the resulting nitrates for nitrogen.
> 
> So you can get little to no ammonia spikes or a silent cycle in the process.
> 
> By limiting the bioload (adding fish slowly) what you will see is at most an initial nitrate spike (20-30 ppm) which will drop down after a few weeks.
> 
> Sometimes you can get a nitrIte spike but usually even that is very short lived. Like a day or two.
> 
> Again that is what I see if you add the fish slowly. And not adding food the first week or so. By dosing large ammmonia you could possibly see longer lasting spikes.
> 
> my .,02


Well, day two of the reset and the Anacharis is starting to consume the ammonia in the tank. Still no nitrites, but it is still a bit early to see if the other measures are more conducive to their growth. Now at this point, as the ammonia falls, should I continue to add ammonia to keep it a constant level, say up to 3ppm? 

As an aside, I crack myself up. I tend to ask questions at times that I am sure cause more experienced hobbyists to think, "Why on earth do you want to go there?" I've had similar responses on other threads similar to that


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## beaslbob

rpadgett37 said:


> Well, day two of the reset and the Anacharis is starting to consume the ammonia in the tank. Still no nitrites, but it is still a bit early to see if the other measures are more conducive to their growth. Now at this point, as the ammonia falls, should I continue to add ammonia to keep it a constant level, say up to 3ppm?
> 
> As an aside, I crack myself up. I tend to ask questions at times that I am sure cause more experienced hobbyists to think, "Why on earth do you want to go there?" I've had similar responses on other threads similar to that


I would just let the ammonia fall, add no chemicals including ammonia, make sure there are no nitrItes , add a fish or two and not add food for a week.

But then that's just my .02


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## rpadgett37

beaslbob said:


> I would just let the ammonia fall, add no chemicals including ammonia, make sure there are no nitrItes , add a fish or two and not add food for a week.
> 
> But then that's just my .02


The ammonia level is still at 4ppm which is still really toxic. I will wait till it comes down a bit. And no Nitrites yet.


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## beaslbob

rpadgett37 said:


> The ammonia level is still at 4ppm which is still really toxic. I will wait till it comes down a bit. And no Nitrites yet.


 
sounds like a good plan. Once things start going down IME they drop very rapidily. like in days.

my .02


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## rpadgett37

beaslbob said:


> sounds like a good plan. Once things start going down IME they drop very rapidily. like in days.
> 
> my .02


 I am watching this closely. I am keenly interested in what is happening and what is to come. Appreciate the help, Beaslbob and all.


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## rpadgett37

beaslbob said:


> pH is a function of carbonate, and carbon dioxide (plus the obvious h+ ions and the like).
> 
> Bealsbob, can we return to this.
> 
> Is there a direct relationship between the carbonates in the water and the CO2? So you know where I am coming from, my research into nitrifying bacteria states they use carbon (typically from C02), among other things, from the water to perform their function.
> 
> Trying to figure out how to phrase this, but I would like to understand better where the carbon from CO2 in the water comes from (how is it broken down to be usable) and that relationship with carbonates as measured by KH in the water (if there is a relationship at all).


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## beaslbob

rpadgett37 said:


> beaslbob said:
> 
> 
> 
> pH is a function of carbonate, and carbon dioxide (plus the obvious h+ ions and the like).
> 
> Bealsbob, can we return to this.
> 
> *Is there a direct relationship between the carbonates in the water and the CO2*? So you know where I am coming from, my research into nitrifying bacteria states they use carbon (typically from C02), among other things, from the water to perform their function.
> 
> Trying to figure out how to phrase this, but I would like to understand better where the carbon from CO2 in the water comes from (how is it broken down to be usable) and that relationship with carbonates as measured by KH in the water (if there is a relationship at all).
Click to expand...

Yes there is and perhaps someone can post the actual equations.

There are even charts showing the relationship.

From what I understand that is all based on the relatively realistic assumption that all the buffering comes from the carbonate ion.

And some co2 test kits actually use that relation to measure co2 in the water.

Basically the forward aerobic bacteria actions releases an h+ using up two carbonate ions. Then as the nitrates are consume (either through bacterial or plant action) the carbonate ions are returned.

Removing co2 with plants increases pH. Adding co2 lowers ph. Increasing the carbonate ion lessong the daily pH drop during lights off.

my .02


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## rpadgett37

beaslbob said:


> Yes there is and perhaps someone can post the actual equations.
> 
> There are even charts showing the relationship.
> 
> From what I understand that is all based on the relatively realistic assumption that all the buffering comes from the carbonate ion.
> 
> And some co2 test kits actually use that relation to measure co2 in the water.
> 
> Basically the forward aerobic bacteria actions releases an h+ using up two carbonate ions. Then as the nitrates are consume (either through bacterial or plant action) the carbonate ions are returned.
> 
> Removing co2 with plants increases pH. Adding co2 lowers ph. Increasing the carbonate ion lessong the daily pH drop during lights off.
> 
> my .02


To be more specific, what is happening to CO2 at low KH values?How do carbonate ions in these conditions play into what happens with the CO2? A simpler way to ask this is are CO2 levels higher or lower at low KH values?


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## beaslbob

rpadgett37 said:


> To be more specific, what is happening to CO2 at low KH values?How do carbonate ions in these conditions play into what happens with the CO2? A simpler way to ask this is are CO2 levels higher or lower at low KH values?


 


rpadgett37 said:


> To be more specific, what is happening to CO2 at low KH values?How do carbonate ions in these conditions play into what happens with the CO2? A simpler way to ask this is are CO2 levels higher or lower at low KH values?


 
Although for reef (marine) aquariums, here is an excellent article on the relationship of pH, CO2 and KH. The same general ideas and equations apply as will to FW tanks.


http://reefkeeping.com/issues/2004-09/rhf/index.htm




[URL="http://reefkeeping.com/issues/2004-09/rhf/index.htm" said:


> http://reefkeeping.com/issues/2004-09/rhf/index.htm[/url]]
> 
> 
> 
> 
> 
> A simple way to think of this relationship is as follows. Carbon dioxide in the air is present as CO2. When it dissolves into water, it becomes carbonic acid, H2CO3:
> 
> 3. CO2 + H2O à H2CO3​
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Seawater contains a mixture of carbonic acid, bicarbonate, and carbonate that are always in equilibrium with each other:
> 
> 4. H2CO3ßà H+ + HCO3-ßà 2H+ + CO3--​
> 
> ​


There are several othe graphs in that article also. But notice that lowering CO2 raised the PH at the same KH value.


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## rpadgett37

beaslbob said:


> The lack of bacteria is not a concern with planted tanks.
> 
> What the plants do is first consume ammonia if present.
> 
> But the bacteria are still there and will still consime ammoonia.
> 
> With the plants providing a higher oxygen (and lower co2) each 24 hour period the bacteria will still reproduce and expand.
> 
> As the bacteria expands less and less ammonia is available for the plants which will eventually start using the resulting nitrates for nitrogen.
> 
> So you can get little to no ammonia spikes or a silent cycle in the process.
> 
> By limiting the bioload (adding fish slowly) what you will see is at most an initial nitrate spike (20-30 ppm) which will drop down after a few weeks.
> 
> Sometimes you can get a nitrIte spike but usually even that is very short lived. Like a day or two.
> 
> Again that is what I see if you add the fish slowly. And not adding food the first week or so. By dosing large ammmonia you could possibly see longer lasting spikes.
> 
> my .,02


 Bealsbob, what is happening to the nitrite during the initial cycle with the plants?


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## beaslbob

rpadgett37 said:


> Bealsbob, what is happening to the nitrite during the initial cycle with the plants?


 
I presume it gets converted to nitrate then the plants get that.

By not feeding the first fish added I get a short small nitrIte spike.

my .02

added:

hopefully this will show up. (it doesn't at work. LOL)

http://i492.photobucket.com/albums/rr284/beaslebob/aquariums/20%20FW%20Leiden/fwleiden.jpg


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## rpadgett37

beaslbob said:


> I presume it gets converted to nitrate then the plants get that.
> 
> By not feeding the first fish added I get a short small nitrIte spike.
> 
> my .02


So one would expect to see some nitrite while the planted cycle is going on?


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## beaslbob

rpadgett37 said:


> So one would expect to see some nitrite while the planted cycle is going on?


 
Yes. But no where near the depth and duration as a non planted bacteria only cycle.

On one marine aquarium I got a nitrIte spike that pegged the api test kit (max 5 ppm) for 4-6 weeks, after adding the first fish. That spike dropped down after a week of not adding food and dropped in a day once it started.

In my FW I always lost the fist fish when I fed it during the first week. Alwasy lost it on the 5 day just like clockwork. the second fish added always lived. So once I said **** it and didn't add food the first week, the fish lived and every fist fish after that always lived when I didn't feed the first week.

Before using macro algae in my marine systems I would add fish and not feed the first week. Got a nitrIte spike but it only lasted a day or two at the most.

So using plants to consume "excess" ammonia combined with not adding food the first week, vastly limited the nitrIte spike and most importantly the fish lived and thrived.

my .02


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## rpadgett37

beaslbob said:


> Yes. But no where near the depth and duration as a non planted bacteria only cycle.
> 
> On one marine aquarium I got a nitrIte spike that pegged the api test kit (max 5 ppm) for 4-6 weeks, after adding the first fish. That spike dropped down after a week of not adding food and dropped in a day once it started.
> 
> In my FW I always lost the fist fish when I fed it during the first week. Alwasy lost it on the 5 day just like clockwork. the second fish added always lived. So once I said **** it and didn't add food the first week, the fish lived and every fist fish after that always lived when I didn't feed the first week.
> 
> Before using macro algae in my marine systems I would add fish and not feed the first week. Got a nitrIte spike but it only lasted a day or two at the most.
> 
> So using plants to consume "excess" ammonia combined with not adding food the first week, vastly limited the nitrIte spike and most importantly the fish lived and thrived.
> 
> my .02


 I assume the same process applies with a freshwater tank?


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## beaslbob

rpadgett37 said:


> I assume the same process applies with a freshwater tank?


Yes.

the basic concept of starting the tank balanced out with plant life then doing the rest is so basic that is not only applies to both marine and FW aquariums but any closed enviroment as well.

my .02


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## rpadgett37

Ok. I am sorting this out in my mind. Time for lunch so I will come back to this a little later.


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## beaslbob

rpadgett37 said:


> Ok. I am sorting this out in my mind. Time for lunch so I will come back to this a little later.


 

me too.

lunch is more important. :lol:


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## pop

This is an interesting thread. It seems everyone has reasoned and rationalized themselves into a corner with no way out. There may be hope let’s start to consider not how carbonate hardness effects nitrification process but how does the nitrification process affects carbonate hardness.

By taking in dissolved oxygen and releasing dissolved carbon dioxide nitrifying bacteria respire (breathe) as co2 is released into the water part of the co2 is turned into carbonic acid which exchanges positive or negative ions with the carbon hardness of the water stabilizing the probability of positive hydrogen ions (pH).

When the hydrogen ions are equally positive and negative the pH is 7.0, (I may be incorrect here) when the probability of more positive hydrogen ions than negative hydrogen ions the water is alkaloid and when the probability of greater number of negative hydrogen ions than positive hydrogen ions the water is acid or base. 
This is one possible way that nitrifying bacteria establishes a byproduct effect on pH and carbonate hardness.


The purple possum rides at midnight


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## beaslbob

Pop

I think you got the hydrogen/(h+) and hydorxide (OH-) ions turned around. Or at least their effect on pH. 

H+ are always positive and lower the pH.

OH- are always negative and raise the pH.

You are correct that co2 forms carbonic acid which increase the h+ but that lowers the pH.

And the kH does limit (or buffer) that pH drop.

And the lower co2 levels limit the carbonic acid and therefore raise the PH.

Plant life (plants in FW or algae in FW or marine) consume co2 lights on and do respire at night consuming oxygen returning co2. IME what happens is the tank with sufficent plant life becomes a net consumer of co2 and producer of 02 each 24 hour period. So I test pH just before lights out. If the pH is high the tank is healthy. (at least pH wise) KH will limit the nightly pH drop but even with that pH drop the tank still is consuming the fish's co2 and returning oxygen each 24 hour period.

As a result even fish that are reported as needing soft, low pH water live and thrive fore years. Even if the pH is 8.4-8.8 (api high range test kit. After all a low co2 environment and high oxygen environment can hardly be detremental to any living thing. Even if pH seems very high.

But that's just my .02


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## jaysee

Should be mentioned that no one has seen these "thriving" fish. Or plants for that matter.


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## beaslbob

jaysee said:


> Should be mentioned that no one has seen these "thriving" fish. Or plants for that matter.


So does that mean my comments on the hydrogen and hydroxide ions on ph, and the carbon dioxide effexts were essentually correct. And did those comments add to, clarify, or correct POPs?


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## corina savin

Beaslbob is right: Hydrogen (H) has only one electron (e-). If it donates it, it becomes H+ (proton), it can put it together with another H (in a covalent bond), making H2 (gas) but it cannot accept an electron to become H-.
Mathematically, pH is negative logarithm of the hydronium (H3O)+ ion concentration. Simply said, pH is about proton in water. Acids are those substances (organics and inorganics) capable to donate protons. The relationship between CO2, KH and pH is off topic here.

The OP question was about very low KH at the beginning of the cycle (no plants, fish and hardly any bacteria- nitrifying or others). Yes, living things give off CO2, bacteria included, very little and not important for this topic.

I believe there is no relationship between KH and bacteria of any kind, although I also notice KH drop at the beginning of both of my two recent tanks. I am not sure if the substrate CEC or the driftwood is to blame because I can better explain it this way.


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## beaslbob

Thanks

FWIW I believe that both KH and PH can be depressed during the initial startup cycle until things "mature". In one article the reduction of nitrates actually returns carbonate to the system which was used up by the forward aerobic bacterial action. I do notice a much deeper initial ph drop if there are such things as drift wood or a peat moss substrate. 

What I have noticed is that after that initil cycle (when the bacteria builds up), the pH does rise in my planted tanks. Due to low co2. KH with peat moss stays constant (4 degrees) for at least two years. But with a play sand only substrate kH rises to high values (~19 degrees or more).

GH was similar with 9 degrees with peat moss and 35-40 degrees with play sand.

I am also not aware of any tie in between kh and bacteria.

my .02


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## jaysee

I was speaking to your assertion about fish thriving in water that is vastly different than their preferred chemistry. If I had two cents for every time you've touted your thriving fish as proof of your methods, while providing nothing to substantiate it, I'd have more pennies than I'd care to count. Some fish can survive such conditions better than others, that much is true. While one is certainly free to do this, it's not advisable and it's misleading to insinuate that it's generally safe to do.


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## pop

Hello Beaslbob:
Of course you helped me get my ducks in a row. I had it backwards and for this I say thanks.

 Jaysee there is no need for attitude this is just a friendly talk. I could say I don’t post pictures because of the implied stress the flash creates for the fish but the truth is I am sorry aquarium manager and don’t wish to publicly prove my laziness. As far as hard or soft water fish, it doesn’t matter for this thread.
pop


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## jaysee

Have you noticed how many of the people who post in the advanced section admit to being lazy fish keepers who would rather not show people what their tanks look like? Just an interesting observation. I'm a lazy fish keeper too - agent will tell you ;-) Not that there's anything wrong with that - we are all in the hobby for our own reasons. Sorry for going off topic.


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## rpadgett37

Deleted. No need to post again.


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