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Potassium Bicarbonate and Potassium Phosphate = overdosing?

Nat N

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Hi all,
I currently use Potassium Bicarbonate as a KH adjuster of tap water for my aquariums - raising the KH and adding Potassium at the same time. I need to dose some Phosphate. Is there any risk of overdosing if using Potassium Phosphate and Potassium Bicarbonate at the same time? Is there such a thing at all as Potassium overdosing? I need to raise the KH by 2 points (from 3 to 5 German degrees) and would like to have about 1 PPM more of Phosphate (currently 0.5 PPM to zero in my tap water)...
 

ceg4048

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

Hi,
I'll assume you have some special reason for raising the KH, because 3 is as good as 5 for plants. In any case, add as much of these salts as you want without fear.

Cheers,
 

Nat N

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

Thanks very much!
The reason of raising the KH is paranoia of PH crashes... I am a female after all and can be forgiven for "girlies fears"... :) Seriously speaking, my tap water is not that stable as I would like it to be and rather than testing it every time in case the KH is lower than 2, I add Potassium Bicarbonate. As you cleared the fears I got from other internet sources on overdosing Potassium, I am off shopping - for Potassium Phosphate that is! :)
 

ceg4048

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

Hi,
I think you should actually try and crash your pH just to come to terms with your fears. By the way, what exactly is supposed to happen if your pH crashes? No one has ever explained this. Do all the fish die? This is another curious tale I wish I knew the origin of...

Cheers,
 

gmartins

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

My tap is amongst the softest you can find with virtually no gH or kH. When I tested this (a few years back) they were all 1. In addition, I use amazonia which is supposed to lower kH and pH and I inject lots of CO2 which also lowers pH. I haven't tested my pH in a while but I can garantee you that all my plants and animals are just fine! Just make sure you pick soft-water fauna (e.g. tetras, rasboras, etc...).

cheers,

GM
 

Nat N

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

Hi all,
Thanks for the replies. Hmmm... this really made me thinking: my fears of PH crashes... I have read horror stories about fish suffocating and plants melting... but are these really true but not somewhat exaggerated?... Maybe crashing the PH on purpose is what I need to do?
If you read Walstad’s book, she states that soft water plants actually thrive in “hard” water whereas the hard water ones perish in soft water... I have a nice little jungle of Vallis Nana in one of the tanks and this plant definitely does better if the KH stays at a certain level...
I do not keep any “hard water” fish and do tend to like “softies” most. My tap GH is about 7 and I use de-ionized water to top up evaporation to keep everything more or less at the same level. I suspect my tap water does not have any Potassium hence adding Potassium Bicarbonate seems to be beneficial. The tap water used to have ample supply of Phosphates but this suddenly changed (another water source?) so Phosphates are now a deficiency.
So, I did go shopping yesterday and waiting for the delivery now....
Gmartins, as a matter of curiousity – if you happen to be in the mood to test your water, I would love to know the results!
 

ceg4048

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

Yes there are lots of exagerations, but mostly there are illogical or irrational conclusions drawn from circumstantial evidence. Most people don't even know what pH is. I mean, have you actually thought about what pH is actually a measure of? It's just a ratio of one ion to another. In fact pH can be an acronym for "percent of Hydrogen ion (H+)". Low pH means high concentration of H+, and this can only happen if acids are added to the water.

In a tank acids are produced just from the breakdown of waste products. If you clean you tank regularly then this waste is removed, but even if you don't the acidic level of the water can't just all of a sudden fall off a cliff unless you dump acid in the tank yourself.

Most of the fish we keep are from highlky acidic waters like The Amazon River Basin where the pH of some streams can fall to 2 or 3. So even if there was suddenly a crash these fish would not be affected in the way it's claimed.

Here is an example of a tank where the KH was kept at 2 and the pH kept at about 3 with a combination of RO water and CO2 injection (The Apistogramma in the middle was breeding in the tank.):
2508506070038170470S600x600Q85.jpg


There was no crashing or melting or any of that. Flora and fauna just carried on. This does not mean that plants never melt or that fish never suffocate, but when they do, it's not because of pH crashing. Plants melting occurs when they are starved of CO2. Fish suffocation happens when there is too much CO2. But we have not had a very accurate way of knowing the CO2 levels in our tanks - not unless we spend thousands of pounds buying scientific equipment to measure it, so people don't really know what the CO2 levels are and since they cannot measure it they attribute all the faults they observe to something that they can measure. This is like losing you purse while walking down a dark alley and then looking for the purse on the High Street because there's more light on that street than in the alley. Doing that, you'll never find your purse and you'll never solve the problems in your tank by blaming everything on pH.

In any case, there's nothing wrong with buffering your water some more with bicarbonate. It's not really a big deal and it does no harm. It's the misunderstanding that does the harm.

There are really not that many plants which really need to be in soft water - only a handful, really and the some of these do OK in hard water (I haven't tried all of them). On the other hand, soft water is not what does damage to the so called hard water plants. The reason that some plants don't do well in soft water has to do more with the nutrient levels which are typically kept low by those who want to maintain the low TDS. So again, cause and effect gets confused because the softness gets blamed when the real culprit is nutrient deficiency, which you have noted with your Phosphate situation. Vallis is grown at many different KH values, however, in non-CO2 tanks, when the CO2 drops below some threshold value this plant is able to use bicarbonate to produce CO2. In a CO2 injected tank Vallis does not care about the KH because there is plenty of CO2.

The most important items in a planted tank are CO2, nutrients and avoidance of dibilitating excess of lighting. These have the biggest impact and pH/KH/GH has relatively minor impact.

Cheers,
 

Ady34

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

ceg4048 said:
On the other hand, soft water is not what does damage to the so called hard water plants. The reason that some plants don't do well in soft water has to do more with the nutrient levels which are typically kept low by those who want to maintain the low TDS. So again, cause and effect gets confused because the softness gets blamed when the real culprit is nutrient deficiency, which you have noted with your Phosphate situation. Vallis is grown at many different KH values, however, in non-CO2 tanks, when the CO2 drops below some threshold value this plant is able to use bicarbonate to produce CO2. In a CO2 injected tank Vallis does not care about the KH because there is plenty of CO2.

The most important items in a planted tank are CO2, nutrients and avoidance of dibilitating excess of lighting. These have the biggest impact and pH/KH/GH has relatively minor impact.

Hi Ceg,
its finally sinking in for me about all these water perameters and there relative unimportance. Ive constantly battled low gh and kh and the penny has finally dropped that its all about nutrients, c02, distribution and good tank maintenance. Learning the fundamentals of nutrients and that low gh may have deficiencies of Mg and Ca which is more of an issue than the gh reading itself is the key. It doesnt matter what the gh or kh readings are if youre providing adequately for the plants needs with ferts and c02.
With reference to this are you more of an advocate of the EI dosing method to ensure all the nutrient demands are met and would you suggest that this method may be better for softer water set ups in particular which are possibly more likely to suffer mineral deficiencies. I only ask as im currently using tpn+ and have recently also began dosing Mg Ca and K mineral salts to increase there availability to the plants (due to some issues encountered), would ei provide the levels of all nutrients needed without the need for additional minerals, or to some degree is there always a need to add extras?
Cheerio,
Ady.
 

ceg4048

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

Ady34 said:
..It doesnt matter what the gh or kh readings are if youre providing adequately for the plants needs with ferts and c02...
Yes, exactly. Even if a plant does have some parameter preference it just means that you may need to provide it with a little more nutrition and a little more CO2 to overcome the inefficiency caused by being outside of the preferred range. There really are only a few plants out of the 300+ varieties that are stubborn and which absolutely demand that you stay within a specific range.

Ady34 said:
...With reference to this are you more of an advocate of the EI dosing method to ensure all the nutrient demands are met...
Yes this is THE Prime Directive of EI.


Ady34 said:
...and would you suggest that this method may be better for softer water set ups in particular which are possibly more likely to suffer mineral deficiencies...
Well, the people who are hypnotized into think that only soft water can be used for plants are coincidentally also often under the impression that nutrients in the water column cause algae. There are a lot of myths built upon myths, so there is a psychological and sociological component at work as well. The most important nutrients are Carbon, Nitrogen, Phosphorous and Potassium in that order. These are called "macronutrients" , "macro" referring to large scale and in this sense meaning that the plant needs large quantities of these elements. And these components can be poorly available in hard water as well as in soft water, especially if the hobbyist uses a lot of light, which increases the demand for these nutrients, or if flow and distribution of water in the tank is not delivering these nutrients at a fast enough rate to sustain their food production and health. So it's not that EI has a greater relevance for soft water versus hard water because there are many ways for a plant to starve, regardless of the water type. What is typically true about soft water though, as we discussed earlier, is that the "micronutrient" levels in soft water are typically absent (or are at a concentration level below the required threshold); Iron, Calcium, Magnesium, Manganese, Zinc, Copper and so forth.

Because the availability of macronutrients is much more important, and is more of an imperative, the EI dosing scheme has special emphasis on the macronutrients NPK, but micronutrients are not ignored, just that the quantities of dosed micronutrients are a lot smaller - because they don't need to be available in large quantities as the macros do. EI does not address Calcium or Magnesium because of the wide variety of water types available, so as a community we agree that these salts can be added to suit. Ca/Mg dosing is therefore an adjunct to the EI dosing program, i.e. add these if you need them for soft or otherwise deficient water, and leave them out if the water supply is enriched with Ca/Mg.
Check the Tutorial section of the forum for the article discussing EI in more detail.

By the way, TPN+ contains Mg. In any case, as I mentioned, because water types vary so much across the world EI focuses on the issues common to all hobyyists, especially the ones who are paranoid about NO3 and PO4. Because there are many things that can go wrong in the tank EI eliminates macronutrient and micronutrient deficiency as a possible cause of poor health. One still needs to address flow/distribution/Ca/Mg, lighting, CO2 techniques as well as maintenance and cleaning, which are all just as important and can all be sources of failed plant health.

Cheers,
 

gmartins

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

Nat N said:
Gmartins, as a matter of curiousity – if you happen to be in the mood to test your water, I would love to know the results!

I would but... I have never bought them again after they finished. I have not a single test at home at the moment.
I do have a drop checker solution though which is a pH test. Can I use this to test my water? Does the amount of water sample influence the reading? What about the colour scale?

cheers,
 

ceg4048

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

Yes, you can use it because as you mentioned, it's exactly the same test reagent as found in the regular pH test kits. If you're using a CO2 injector with a solenoid though your readings will depend on what time of day you measure the tank water pH. The scale should be identical and the amount of test water if it's too much will make the sample paler. Just use the same amount of water that you would use in the drop checker, a couple of ml is all...

Cheers,
 

gmartins

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

cheers Ceg. I do have a solenoid so... I suppose that if I take my sample just prior to lights on this corresponds to the time of the day when pH is lowest right?
 

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

No, at that time it's at it's highest mate. CO2 acidifies the water thereby driving the pH down. The pH might be at it's lowest just before the solenoid turns the gas off.

Actually, thinking about it some more, it would be more accurate to simply take a sample of water, at any time, and just let it sit for 1 hour to allow whatever CO2 is dissolved in it to outgas. This is what you do when you want to find out what the natural pH of your tap water is, so the same works for tank water.

Cheers,
 

Nat N

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

Hi everybody,
Ceg, thanks very much. I know what you mean about misconceptions and “old wives tales” an totally agree with you. I think there is a lot of information/opinions around which are fundamentally wrong as they mix up principles of keeping planted and fish only tanks. These are being circulated, repeated and sometimes grow to enormous proportions. I feel I am a victim of reading too much of “rubbish” myself. I know one person on one of the beginners forum. This person has a university degree in chemistry, has been keeping fish for over 10 years and is a sort of a “guru” for novices on that forum. I understand that the advice given by that person is sometimes invaluable for those who just started but some of the recommendations are simply... how would I put it... daft... And that will be carried around in circles over and over again, unfortunately.
I understand what PH is and the thing what got me confused is the fact that acidic conditions increase the toxicity of metals in water, push down oxygen levels and allegedly make an overdose of anything to be more dangerous. (Am I right or am I confusing myself even further?). Walstad describes an experiment with Val Americana being grown in soft and hard water. According to this experiment, the Val completely deteriorated and eventually died in acidic conditions. Walstad states that Val is one of the plants which prefers uptake of carbon from bicarbonates to uptake from CO2. I noticed myself that adding CO2 makes it growing slower and producing smaller leaves in comparison with non-CO2 conditions where the plant can take up carbon from bicarbonates. However, this may be purely the lack of something else (I am suspecting Phosphates). Hence I wanted to start dosing Phosphates to check if that was the reason. I have 7 tanks (most of them can be classed as nanos or medium sized) – all with different conditions and substrates. The Val Nana is doing great in a 35 litre tank with no CO2 and the Val Americana in a different tank has significantly slowed down after I added CO2 (it is the same tank where Pogostemon Stellata is doing rather well – I am starting to understand what people mean by calling it a “weed”).
As I am thinking over a project of a not biotope but true to a certain locality tank, I discovered that collecting endemic or native plants in one tank may be tricky. I want to create an aesthetically pleasing effect as well, so I am trying to put together plants from the same place but not necessarily from the same river/lake/swamp. This creates a certain challenge as I have to develop a routine/conditions which cater for all of them equally. Hence I am trying to balance between reasonable KH and CO2 injections in one of the tanks where I gradually collect those plants (and the fish from the same locality). I am also trying to develop a routine which is somewhere in between of low-tech and high-tech approach as I work full time and really would prefer to spend more time admiring the tanks than doing maintenance all the time in those very few spare hours I’ve got!
It will be a long learning path – and thanks for clearing some of the things for me.
 

gmartins

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

ok just for the record - I've measured pH over a full cycle and it ranged between 6.8 (in the morning) and 6.0 (during the lights on).
 

ceg4048

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

gmartins said:
ok just for the record - I've measured pH over a full cycle and it ranged between 6.8 (in the morning) and 6.0 (during the lights on).
So using the calculation [Molarity of H+ ions] = (10)**(-pH)
at a pH of 6.8 the concentration of H+ in the water is 0.00000016 moles per liter
at a pH of 6 the concentration of H+ in the water is 0.000001 moles per liter

Therefore, dropping the pH from 6.8 to 6 causes a 562% increase in the concentration of H+

In order to crash the pH from a value of 6 to say a value of 2 you would need to increase the molar concentration of H+ by an additional 999,990% - that's almost 1 million percent. Even at a KH of nearly zero there is nothing in that tank that can produce that amount of H+.
Unless you dump pool acid in the tank, it will never happen. Can you see how crazy the idea of a pH crash is?

Nat N said:
...I understand what PH is and the thing what got me confused is the fact that acidic conditions increase the toxicity of metals in water, push down oxygen levels and allegedly make an overdose of anything to be more dangerous. (Am I right or am I confusing myself even further?)...
I think you're confusing yourself further because the toxicity we are talking about doesn't apply in our tanks. It also depends on what metal we are talking about. For example, Iron, Fe, which is an important micronutrient typically exists in two forms Fe++ (Ferrous) and Fe+++ (Ferric). Ferric Iron compounds have a very low solubility, but as the pH is lowered, the Ferric converts to Ferrous which has a high solubility. So acidity actually helps the plant to uptake Fe, whereas at a higher pH the probability of Iron deficiency is more prevalent. On the other hand, the metal Molybdenum (Mo) which is also a very important micronutrient, has a higher solubility at higher pH, so acid conditions lower the availability of this metal.

Nat N said:
...Ihave 7 tanks (most of them can be classed as nanos or medium sized) – all with different conditions and substrates. The Val Nana is doing great in a 35 litre tank with no CO2 and the Val Americana in a different tank has significantly slowed down after I added CO2 (it is the same tank where Pogostemon Stellata is doing rather well – I am starting to understand what people mean by calling it a “weed”).
But other people grow Vallis fantastically with added CO2 so this cannot be true. There are lots of reasons for the Val in the CO2 tank to have a lower performance, and this may have nothing to do with CO2. In fact it may even be a result of not enough CO2 at the location where the Val is. One of the errors we consistently make is that we assume that we have control of the tank environment, when in fact we have very little control. Plants only can use CO2 in their food production chain. Therefore HCO3 has to be converted to CO2 internally before the plant can use it, therefore it cannot be that HCO3 is a preferred method of carbon uptake. It may be that Val is better than most at using HCO3 however.

Nat N said:
...I am trying to put together plants from the same place but not necessarily from the same river/lake/swamp. This creates a certain challenge as I have to develop a routine/conditions which cater for all of them equally. Hence I am trying to balance between reasonable KH and CO2 injections in one of the tanks where I gradually collect those plants (and the fish from the same locality).
Again, this approach causes more problems than it solves because there really is no need to cater to specific parameters. The plants and fish are highly adaptable. If you concentrate on the things that actually matter, such as good nutrition, good flow and flow distribution, and if you limit the energy of the light, then flora and fauna will make the adaptations.

Cheers,
 

Nat N

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

Hi Ceg,
It’s Clive isn’t it? I did a bit of reading around...
Thanks very much for the reply. For a person with a patchy knowledge like me it is sometimes what puts the final bit into a puzzle but sometimes causes more questions...
So using the calculation [Molarity of H+ ions] = (10)**(-pH)
at a pH of 6.8 the concentration of H+ in the water is 0.00000016 moles per liter
at a pH of 6 the concentration of H+ in the water is 0.000001 moles per liter

Therefore, dropping the pH from 6.8 to 6 causes a 562% increase in the concentration of H+

In order to crash the pH from a value of 6 to say a value of 2 you would need to increase the molar concentration of H+ by an additional 999,990% - that's almost 1 million percent. Even at a KH of nearly zero there is nothing in that tank that can produce that amount of H+.
Unless you dump pool acid in the tank, it will never happen. Can you see how crazy the idea of a pH crash is?
This is pretty much self explanatory and very obviously convincing – thanks.

I have read some opinions – like this:
Quote:
<<<The nitrifying bacteria which oxidise ammonia in to nitrate use 4.8 grams of oxygen is used, 7.14 grams of calcium carbonate (or other carbonates) for every gram of ammonia converted in to nitrate.
The oxygen replenishes itself at the water surface but the carbonates have to be replenished by either water changes or by adding buffers to the water. It is the carbonates which hold the pH stable, so as the carbonates become depleted the pH will begin to fall. If you get to a point where the carbonates are completely depleted the pH will crash and biological filtration will stop.>>>
Unquote.
I suppose, this is not relevant/true for planted aquariums for many reason (production of oxygen by plants and a much smaller contribution of bacteria into the general balance e.g. uptake of ammonia by plants, etc. etc...)
This is from another forum – you see why I keep on getting all confused? To be honest, I am not sure I need to buffer the KH in my tanks any more – the Potassium will be added by dosing Potassium Phosphate anyway.
I think you're confusing yourself further because the toxicity we are talking about doesn't apply in our tanks. It also depends on what metal we are talking about. For example, Iron, Fe, which is an important micronutrient typically exists in two forms Fe++ (Ferrous) and Fe+++ (Ferric). Ferric Iron compounds have a very low solubility, but as the pH is lowered, the Ferric converts to Ferrous which has a high solubility. So acidity actually helps the plant to uptake Fe, whereas at a higher pH the probability of Iron deficiency is more prevalent. On the other hand, the metal Molybdenum (Mo) which is also a very important micronutrient, has a higher solubility at higher pH, so acid conditions lower the availability of this metal.
Walstad highlights an example of somebody trying to combat Phosphates in their tank by adding FECl3. They reported what they thought was signs of Phosphate deficiency which she promptly dismissed as Iron toxicity in plants. According to her, such thing as toxic destructive levels of Iron can happen... (page 13 of her book). She also states that chlorosis and Iron deficiency in plants can be caused by excess of Copper, Manganese and Zinc (the same page). She does, however, state that PH between 6 and 8 is “safe” in respect of metal toxicity...
I seem to quote and refer to Walstad’s book an awful lot. It is not because I completely agree or take her findings as an ultimate guideline. I deeply respect her and wish that Tom Barr would write a book as well – it will be some other very valuable opinion to take in, re-work and use depending on individual preferences, goals and conditions. I do not want to go Walstad’s El Naturel approach but find some of the things she explains very valuable and a food for thought.
Again, this approach causes more problems than it solves because there really is no need to cater to specific parameters. The plants and fish are highly adaptable. If you concentrate on the things that actually matter, such as good nutrition, good flow and flow distribution, and if you limit the energy of the light, then flora and fauna will make the adaptations.
Yep, I think I have only to agree with you. I apply this method to terrestrial plants which I grow quite successfully so should really apply the same to the aquatics without complicating my routine.

I started dosing Potassium Phosphate and will see what happens.

By the way, Gmartins report on the PH fluctuating from 6 to 6.8 – is it not quite a lot of difference? Some people use solenoids to switch the CO2 supply off at dark time. I have not got one yet but probably it is a good idea – economy and plus more stable CO2 level?
 

ceg4048

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

Nat N said:
I have read some opinions – like this:
Quote:
<<<The nitrifying bacteria which oxidise ammonia in to nitrate use 4.8 grams of oxygen is used, 7.14 grams of calcium carbonate (or other carbonates) for every gram of ammonia converted in to nitrate.
The oxygen replenishes itself at the water surface but the carbonates have to be replenished by either water changes or by adding buffers to the water. It is the carbonates which hold the pH stable, so as the carbonates become depleted the pH will begin to fall. If you get to a point where the carbonates are completely depleted the pH will crash and biological filtration will stop.>>>
Unquote.
I suppose, this is not relevant/true for planted aquariums for many reason (production of oxygen by plants and a much smaller contribution of bacteria into the general balance e.g. uptake of ammonia by plants, etc. etc...)
This is from another forum – you see why I keep on getting all confused? To be honest, I am not sure I need to buffer the KH in my tanks any more – the Potassium will be added by dosing Potassium Phosphate anyway..
Well, there are so many processes going on that, as you mentioned, effects of some processes cancel the effects of others.
Here is a typical 1st stage aerobic bacterial nitrification equation:
(NH4+) + 1.5(O2) ----> (NO2-) + 2(H+) + (H2O)

The 2nd stage looks something like this:
(NO2-) + 0.5(O2) -----> (NO3-)

Now, really, lets forget about calcium carbonate for a second, because it's clear from these equations that because these are aerobic, a lot of Oxygen is being used to convert Ammonia to Nitrate. Lack of Oxygen kills a lot of fish in tanks so if there was a pH crash (which we know is unlikely) and if these bacteria decided to stop nitrification due to low pH, the plants will absorb the ammonia, and will do so without adversely affecting the Oxygen levels. Isn't this a good thing? Who cares if pH drops and Nitrosomas /Nitrobacter decide to take a vacation as a result? In any case, a pH of 6 does not mean that these microbes stop functioning. It just means that they don't nitrify as much as if the pH were at 8.0. Also, ammonia is less toxic as the pH falls because it converts to a higher ratio of NH4+ - so lowering the pH does more good things than bad things. I don't really see a problem here. Higher Oxygen due to direct plant uptake of ammonia/ammonium (plus extra Oxygen expulsion from photosynthesis), better plant health, lower toxicity of any ammonia/ammonium that is not immediately taken by the plants. I can't see why this is even an issue.

Nat N said:
Walstad highlights an example of somebody trying to combat Phosphates in their tank by adding FECl3. They reported what they thought was signs of Phosphate deficiency which she promptly dismissed as Iron toxicity in plants. According to her, such thing as toxic destructive levels of Iron can happen... (page 13 of her book). She also states that chlorosis and Iron deficiency in plants can be caused by excess of Copper, Manganese and Zinc (the same page). She does, however, state that PH between 6 and 8 is “safe” in respect of metal toxicity...
Well, as I mentioned in an earlier post, I've doses massive amounts of metal micronutrients in my tanks and I have never seen metal toxicity in plants at any pH - and I'm generally considered to be an extremist as regards dosing. I probably dose higher quantities of nutrients than anyone else in the known world (or at least I'm in the top 10, I reckon). I can't recall who it was, but I was embroiled in a bitter argument with one of those lean dosing acolytes, and they referred to me as "The High Priest of Nutrient/CO2" because I kept telling people to "add more", "add more" of everything.

Here is a tank dosed with 3-4X the EI suggested macronutrient levels, 6X the EI micronutrient levels (3ppm Fe) and enough CO2 to drive the tank water down to a pH of around 5 (although, this is not quite the same as your conditions because the KH and GH were high). I did this specifically to test the theory of low pH and nutrient toxicity. I failed to induce any form of toxicity in any plant doing this. It is possible that the toxicity issues arise if the plant is in an emmersed state and not submersed. There is no "practical" limit to the amounts of metal micronutrient you can add or practical lower limit to the pH in which you can grow excellent plants in. What's more important is that you feed ample levels of nutrients, have excellent CO2 without damaging your fish, have good flow energy, to distribute that flow properly, to not go crazy with lighting and to keep the tank spotlessly clean via frequent and massive water changes. These are enough things to worry about, believe me. You don't need to worry about all that other stuff. It's all good to know, but ultimately it's irrelevant. The more you worry about things that don't matter, the more trouble you'll have.
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Here I lowered the CO2 injection to allow more fish. This caused the pH to rise to a minimum daytime level of about 6. But remember that it isn't the fact that the ph rose that allows the fish thrive, it's the fact that the CO2 toxicity level was reduced. The net effect was a rise in the pH. So this highlights the second and perhaps more important point that when we measure the waters pH it's necessary to understand WHY the pH is at it's value. It's the thing in the water that causes the pH to rise or fall that is important, not the actual pH value itself. I think that's what people completely disregard when analyzing these parameters. It's this poor analysis that often renders the parameters useless.
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Nat N said:
By the way, Gmartins report on the PH fluctuating from 6 to 6.8 – is it not quite a lot of difference? Some people use solenoids to switch the CO2 supply off at dark time. I have not got one yet but probably it is a good idea – economy and plus more stable CO2 level?
Yes, you are absolutely right. This is a humongous difference. It's a 6X increase in acidity and I'd even go as far as to say that Gmartins would do even better to have pH fluctuation of at least 10X instead of 6X. Neither his fish nor his plants care about this and that's what we are trying to get through to people - to forget about pH stability because you will not see any practical benefits to maintaining a stable pH. This adds no value whatsoever unless you are breeding fish.

Cheers,
 

bigmel

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

ceg4048 said:
Hi,
I think you should actually try and crash your pH just to come to terms with your fears. By the way, what exactly is supposed to happen if your pH crashes? No one has ever explained this. Do all the fish die? This is another curious tale I wish I knew the origin of...

Cheers,


Hi mate

Ph crashes are very real in areas of soft water with koi pond owners, although i have never come across this keeping tropicals due to regular water changes i have had a few near miss,s on my koi pond . Due to the heavy feeding the bacteria use up the kh very quickly and i buffer regulary with bicarb .

I hardly bothered checking my ph on indoor tanks for over 20 years with no problems ,but my ph can drop like a stone on a 500 gallon indoor pond and outside 2700 gallon with heavy feeding .

Theres some info here ...http://www.mankysanke.co.uk/html/questi ... wered.html

The link is koi pond related , and i feed 1/4 kilo a day in summer and this causes the kh to get used up very quickly and my kh is only 1 from the tap so i have to buffer to 4 in the pond but still it drops quickly even with water changes .

I doubt this would concern the average aquaruim keeper who does regular water changes and feeds tiny tetra, shrimp etc but a tank with a low kh ,over stocked with big trops and over fed with neglected water changes and it could happen ?

Just thinking out loud i,m here to learn :D
 

roadmaster

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Re: Potassium Bicarbonate and Potassium Phosphate = overdosi

With EI dosing scheme,GH booster/equilibrium,50 % weekly water changes, used in many planted tanks, I'm not sure pH crash could happen, unless you also remove that which buffers the water,stop water changes, or drive it down with CO2 No?
Plant's and fishes may not feel pH, but I believe both would be affected to varying degrees with lack,or excess of dissolved minerals that influence dh,KH no?
 

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