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Phosphate in tapwater

jaypeecee

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I know many dismiss the accuracy of test kits but I find JBL more reliable provided you follow the instructions and apply some common sense. Anyway my result was immediately dark blue and the scale of JBL only goes to 1.8ppm and my assumption was that this was high and possibly an issue?
Hi @Luvlyjub

I use the JBL PO4 (sensitive) test kit and it serves me well. As you have noted, the maximum reading that it can handle is 1.8 ppm. In order to measure in excess of this figure, it is necessary to dilute the tank water sample or tap water sample using RO/DI, low conductivity rainwater or distilled water. So, if you were to dilute the tank or tap water sample with an equal amount of RO/distilled water, that would be a factor of two dilution. From this diluted sample, you would still use 10ml in order to carry out the test. This principle can be extended to increase the upper PO4 limit. Now, let's say that this time around, the diluted sample matches the 1.2 ppm colour patch. You'd simply multiply this by 2, which would give you 1.2 x 2 = 2.4 ppm.

I hope that's clear.

Please let us know the outcome and then we can discuss this further.

JPC
 

MichaelJ

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Michael - I note your post with interest that you maintain high phosphate but does this not deplete over the period with uptake from the plants?
Hi @Luvlyjub Yes, I have kept dosing 10ppm with my weekly WC for a long time. I mix in the KH2PO4 (along with my other salts) targeting my 40% WC water with 10ppm of PO4 to to maintain that level in the tank minus the uptake. My tanks are densely planted, but low-energy, so I guess the uptake is fairly low - perhaps a net change of -1 ppm/wk. So, my guesstimated equilibrium level is probably around 8.5 ppm. (I don't have much buildup from waste...).

Would I be right to assume that an optimum PO4 level (if there is one) is relative to the density of planting and type of ferts you are using.
I think plant mass always has to be taken into consideration.

And then if a higher PO4 does inhibit GSA does it not then have a potential negative impact with other types of algae or is this only in combination with N?
I haven't noticed ANY negative impact from the high PO4 (or high N/NO3, K or Fe dosing for that matter)... I have excellent plant health, zero algae to speak of (I rarely even have to clean the inside of my front glass) So my overall maintenance routine with all it entails, have definitely been working out long term in both my tanks.

Now, my two tanks are very similar in terms of stocking level and especially plant mass and in light of recent long-running discussions about fertilization I am currently contemplating slowly putting one of my tanks on a "diet" and apply some of the lean-dosing ideas that some fertilizer experts seems to have good success with. My agenda is to see if I can make a dent in my TDS for the benefit of my livestock while maintaining the same level of plant health. Its probably going to be some sort of hybrid approach as I need to maintain certain levels for my shrimps (such as Ca and Mg ppm's).

Cheers,
Michael
 

Luvlyjub

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Please let us know the outcome and then we can discuss this further.
OK so with JBL test diluted tap water with DI 50% and then 25% I come up with a consistent 2.4ppm PO4.

The questions are -

Should I just accept this level in my tap water and use in my aquariums without trying to reduce?
Is such level in the goldilocks zone to inhibit GSA (if proven) or is it too high and a propensity to cause other potential algae issues?
Is the concern with PO4 levels dependent on level of plant mass and type of ferts used?

Michael - I note that your method is to maintain a high PO4 in excess of the plants requirements and from your experience have little algae issues.

I suppose each circumstance is different as algae has a number of influencers and I guess I am trying to point the finger at a potential culprit with the phosphate level. As I have been oblivious to the phosphate in my tap water and therefore aquariums for 20 years I wonder if I really need to be concerned but welcome advice from others.
 

Jaseon

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Hi @Jaseon

Yes, phosphorus (as phosphate) is very important to bacteria. But, it's important to all living things as ATP* is fundamental to life (as we know it).

* Adenosine Triphosphate

JPC
I was going off what Dr Tim mentioned how Heterotrophic bacteria was using up the phosphate robbing the nitrifiers.
 

arcturus

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Should I just accept this level in my tap water and use in my aquariums without trying to reduce?
Is such level in the goldilocks zone to inhibit GSA (if proven) or is it too high and a propensity to cause other potential algae issues?
Is the concern with PO4 levels dependent on level of plant mass and type of ferts used?
1. There is no "proven" way to inhibit GSA; not even the factors that limit or stimulate GSA (and most other algae) are well understood.

2. You should not be concerned with "excess" macronutrient levels, including PO4, but with nutrient deficiency (and availability and distribution of CO2).

3. <Some studies (see snippet below)> link the N : P ratio (and not their absolute concentration) to algae limitation and stimulation. For example, Barr's EI proposes a 10:1 N : P ratio. <Other methods, such as the Redfield>suggest 16:1.

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jaypeecee

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Hi @arcturus

You may find the following to be of relevance:


JPC
 

arcturus

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Hi @arcturus

You may find the following to be of relevance:


Thanks! There are many open questions. It is hard to correlate the ratios found in natural environments with their actual impact. The worse part of it is that many correlations are scientifically weak since they rely in simple observations with few or no controlled variables. And it is even harder to extrapolate the correlations to planted aquariums...
 

ceg4048

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Should I just accept this level in my tap water and use in my aquariums without trying to reduce?
Yes.
Is such level in the goldilocks zone to inhibit GSA (if proven) or is it too high and a propensity to cause other potential algae issues?
No. Add as much PO4 as you like. There are no repercussions of high PO4, only of low PO4.
There is no "Goldilocks Zone". Required nutrient uptake is a function of light intensity, temperature and nutrient availability. It therefore changes as these variables change.
I wonder if I really need to be concerned but welcome advice from others.
Fretting about high PO4 levels in a freshwater planted tank is fruitless.
3. <Some studies (see snippet below)> link the N : P ratio (and not their absolute concentration) to algae limitation and stimulation. For example, Barr's EI proposes a 10:1 N : P ratio. <Other methods, such as the Redfield>suggest 16:1.
There is no relationship in our tanks of N to P ratios with algal blooms. The related blooms occur as a result of any limitation of N or P. Barr does not suggest a magical ratio in order to deter algae. His ratio was determined by the simple arithmetic based on the numbers used when the values of each were determined to be unlimited.

Cheers,
 

jaypeecee

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Thanks! There are many open questions. It is hard to correlate the ratios found in natural environments with their actual impact. The worse part of it is that many correlations are scientifically weak since they rely in simple observations with few or no controlled variables. And it is even harder to extrapolate the correlations to planted aquariums...
Hi @arcturus

Scientific information is plentiful for those who go looking for it. But, it's not everyone's idea of fun. Determined, as I have been, to obtain facts, I now have a small library of scientific papers dealing with virtually all subjects of interest (to me) in the field of freshwater aquatics. As you can imagine, little scientific work has been done in the aquatics hobby per se. But, there are notable exceptions - such as the pioneering work of Dr Tim Hovanec relating to nitrifying bacteria.

If the science behind our hobby is of interest to you, do you have a copy of Diana Walstad's Ecology of the Planted Aquarium? This book has taught me a great deal about planted aquaria. In this book, she also makes numerous references to the seminal work by Robert G Wetzel - Limnology (3rd Edition).

JPC
 

arcturus

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There is no relationship in our tanks of N to P ratios with algal blooms. The related blooms occur as a result of any limitation of N or P. Barr does not suggest a magical ratio in order to deter algae. His ratio was determined by the simple arithmetic based on the numbers used when the values of each were determined to be unlimited.
I am aware of reports of successful planted tank keepers that seem to show that these ratios are not relevant. But there are other successful planted tank keepers that report otherwise. Are any conclusive (scientific) studies that demonstrate that such ratios do not correlate to algal blooms in planted tanks? Can we dismiss N : P : K ratios, and other ratios such as Ca : Mg?

The fact is that there are <studies> <analyzing> <the role of> of the N : P, N : K ratio and other ratios and limitation factors in natural ecosystems. There are also studies suggesting the importance of <the interplay between multiple factors>, which would be unsurprising since we are dealing with a dynamic <complex system>. If there were definitive answers to these questions, then we wouldn't have so many different approaches to planted tank keeping but a general framework that would apply to a majority of setups, which is not the case.
 

dw1305

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Hi all,
If there were definitive answers to these questions, then we wouldn't have so many different approaches to planted tank keeping but a general framework that would apply to a majority of setups, which is not the case.
<"Same for me really">, too many <"unknown unknowns"> to quantify exactly what is happening. I think I know (understand?) how you can keep <"low tech tanks fairly stable">, but I don't have any empirical evidence.

cheers Darrel
 

jaypeecee

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Hi Everyone,

If I have time today, I will try to pull together some scientific studies and hobbyists' observations/data that are very relevant to the topic(s) being discussed here.

JPC
 

Ria95

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3. <Some studies (see snippet below)> link the N : P ratio (and not their absolute concentration) to algae limitation and stimulation. For example, Barr's EI proposes a 10:1 N : P ratio. <Other methods, such as the Redfield>suggest 16:1.
It's often useful to play a though experiment. If ratios of N : P :K are an important aspect leading to algae growth in aquariums then it will be easy to induce (and stop ?) algae blooms. The 'faulty ratios' will also be common across many tanks experiencing algae blooms and many concentrations (more on this later). We have seen such strong interdependence situations with the light-CO2-nutrients triangle.
If however the rations of N : P :Kare not an important aspect that determines algae growth in the aquarium there will be aquariums with algae and aquariums without algae at the same ratios, aquariums without algae blooms at a wide range of ratios. The experiments to induce the algae blooms would be non-repeatable or will not apply across a wide range of light, CO2 levels and concentrations. In practice other aspects will fix the algae bloom then coming to a "N : P :K ratio of algae limitation". In other words N : P :K would be just one of the many small factors that may or may not influence a little bit if there is a bloom or not in our aquariums.

TLDR: Makes sense, if N : P :K plays a very important aspect of algae blooms it will be very common across many other variables and it will be very easy to induce algae with it.
I am aware of reports of successful planted tank keepers that seem to show that these ratios are not relevant. But there are other successful planted tank keepers that report otherwise. Are any conclusive (scientific) studies that demonstrate that such ratios do not correlate to algal blooms in planted tanks? Can we dismiss N : P : K ratios, and other ratios such as Ca : Mg?

The fact is that there are <studies> <analyzing> <the role of> of the N : P, N : K ratio and other ratios and limitation factors in natural ecosystems. There are also studies suggesting the importance of <the interplay between multiple factors>, which would be unsurprising since we are dealing with a dynamic <complex system>. If there were definitive answers to these questions, then we wouldn't have so many different approaches to planted tank keeping but a general framework that would apply to a majority of setups, which is not the case.
If N : P ratios are relevant over concentrations then the same effect on algae amount and type will occur at
  • 10 mg/L N ,1 mg/L P; N : P 10:1
  • 0,01 mg/L N, 0,001 mg/L P ; N : P 10:1
-100 mg/L N, 10 mg/L P; N : P 10:1
If you don't get the same effect it may be more worth to look at concentrations than ratios.
The same rationale applies to effects of ratios on plant quality and growth rate. Few proponents of various golden ratios bother to test the same ratio across 2 logs of concentration to check if indeed it is the ratio that makes the effect. Quite the contrary, as more data comes in the same proponents of the golden ratio start saying ' it works across quite a large range of ratios', 'you don't have to be that specific' and add some footnotes ' as long as X is kept above this value'. The golden ratio remains as optimal somehow, just through inertia.

For example, Barr's EI proposes a 10:1 N : P ratio.
As far as I have seen the Estimative Index never recommended ratios, even less 10:1 N : P. In the original article the recommended ranges for EI are:
"
CO2 range 25-35ppm
NO3 range 5-30ppm
K+ range 10-30ppm
PO4 range 1.0-3.0 ppm
Fe 0.2-0.5ppm or higher (?)
GH range 3 degrees ~ 50ppm or higher
"
If you really want to force ratios out them you have between 3.5:1 to 6.9:1 N : P--not 10:1. If you want to use the figures from Rotala Butterfly | Planted Aquarium Nutrient Dosing Calculator for EI you still end up with a ratio of 4:1 N : P by mass, very far from the referenced 10:1. I have to think part of the high PO4 dosage is to counteract the phosphate fearmongering at the time EI was published, the nutrient fearmongering seems to be blooming again.
 

jaypeecee

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There is no relationship in our tanks of N to P ratios with algal blooms. The related blooms occur as a result of any limitation of N or P. Barr does not suggest a magical ratio in order to deter algae. His ratio was determined by the simple arithmetic based on the numbers used when the values of each were determined to be unlimited.

Hi @ceg4048

Please take a look at the following link - Tom Barr's entry. Then scroll down to Roger Miller's entry. I suspect the figures being discussed had their origin in the Redfield Ratio (RR). My understanding is that the RR is now not considered to be applicable to the aquarium ecosystem. At this point, it may be best to go to The Krib discussion:


I'm sure you will have read this disscussion before but other UKAPS members may be new to it. OK, I now have a question for you. And that is - when you say "There is no relationship in our tanks of N to P ratios with algal blooms. The related blooms occur as a result of any limitation of N or P". Are you referring to all forms of N and P that exist in our tanks?

JPC
 
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arcturus

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(...) TLDR: Makes sense, if N : P :K plays a very important aspect of algae blooms it will be very common across many other variables and it will be very easy to induce algae with it.
Are you saying that by keeping light and CO2 constant you cannot trigger algal blooms through the variation of NPK ratios and concentrations?

(...) The same rationale applies to effects of ratios on plant quality and growth rate. Few proponents of various golden ratios bother to test the same ratio across 2 logs of concentration to check if indeed it is the ratio that makes the effect. Quite the contrary, as more data comes in the same proponents of the golden ratio start saying ' it works across quite a large range of ratios', 'you don't have to be that specific' and add some footnotes ' as long as X is kept above this value'. The golden ratio remains as optimal somehow, just through inertia.
Studies in natural ecosystems (such as the ones I linked), do not separate the analysis of concentrations from the ratios. They are two sides of the same coin. Algal blooms are correlated to nutrient ratio at a given concentration. In short, it is not only about the ratio, but ratio at a given ppm. Whether these observations in natural ecosystems apply to planted tanks or not is another question.

(...) If you really want to force ratios out them you have between 3.5:1 to 6.9:1 N : P--not 10:1. If you want to use the figures from Rotala Butterfly | Planted Aquarium Nutrient Dosing Calculator for EI you still end up with a ratio of 4:1 N : P by mass, very far from the referenced 10:1.
The EI target is 30 ppm NO3 to 3 ppm PO4. That is 10 : 1. That gives roughly 4.5 : 1 of N : P. So, we are talking about the same thing using different units.
I have to think part of the high PO4 dosage is to counteract the phosphate fearmongering at the time EI was published, the nutrient fearmongering seems to be blooming again.
This is not about nutrient fearmongering but about scientific evidence. Either there is validated data sustaining that the ratios and their underlying concentrations are irrelevant on a planted tank or there is not. Otherwise, you cannot make the false inference that EI "works" (which is far from being a universal fact) because ratios play no role. We should not worry about about nutrient fearmongering, but about promoting the potential virtues of a method while dismissing open questions without any scientific basis.
 
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Ria95

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The EI target is 30 ppm NO3 to 3 ppm PO4. That is 10 : 1. That gives roughly 4.5 : 1 of N : P. So, we are talking about the same thing using different units.
I'm using mg/L or ppm. I will make no assumption about you, but the two below are still saying different things with all the units I'm aware of.
For example, Barr's EI proposes a 10:1 N : P ratio. <Other methods, such as the Redfield>suggest 16:1.
The EI target is 30 ppm NO3 to 3 ppm PO4. That is 10 : 1.
Worth mentioning that the Redfield 16:1 N : P is a molar ratio? Which highlights another issue with ratios, doesn't it? If you want to make it more comparable it's closer to 7.2 :1 N : P by mass. If you want to support the hypothesis about ratios you have to pay attention to these things.

Are you saying that by keeping light and CO2 constant you cannot trigger algal blooms through the variation of NPK ratios and concentrations?
With the quoted text?, no. In general? I can trigger algae blooms by low concentrations of nutrients leading to plant health issues and lack of growth which gives the algae an advantage. The nutrient ratios are all over the place during the week but the tanks seems to not experience algae blooms. Thankful for that :) . Keeping algae separated by the side is pretty easy in many nutrient concentrations. They are quite hardy.
Either there is validated data sustaining that the ratios and their underlying concentrations
So if I say N:Fe 100:1, I'm curious what is the underlying concentration ? Really am because I cannot make sense of it.
If I say 10 mg/L NO3-N and 0.1 mg/L Fe I am a lot clearer. So what is the advantage of ratios if you cannot scale them up or down but still depend on concentrations?

This is not about nutrient fearmongering but about scientific evidence. Either there is validated data sustaining that the ratios and their underlying concentrations are irrelevant on a planted tank or there is not. Otherwise, you cannot make the false inference that EI "works" (which is far from being a universal fact) because ratios play no role. We should not worry about about nutrient fearmongering, but about promoting the potential virtues of a method while dismissing open questions without any scientific basis.
I think it quite is. It can be approached from a non-biased, non-fearmongering way and I look forward to that, i.e. "I tried this and this is what i got" instead of starting with "what if algae" "it might hurt us" " we need to". It may be only me, but ceg's post reads a lot more free.
No. Add as much PO4 as you like. There are no repercussions of high PO4, only of low PO4.
There is no "Goldilocks Zone". Required nutrient uptake is a function of light intensity, temperature and nutrient availability. It therefore changes as these variables change.
Fretting about high PO4 levels in a freshwater planted tank is fruitless.

The 2 papers you referenced and I can access are about cyanobacteria, one quite species specific. I am not aware of any way it can be generalized from cyanobacteria to the many types of algae we experience in aquariums. Maybe you or someone else does.

Regardless i have suggested quite straightforward ways to support the hypothesis and form the start of a scientific basis with a series of tests where you can show how important N: P :K is. Others have tried here and there but they still end saying the things i quoted. Plants and algae are adaptable like that, few things break if you go from 4:1 to 3:1 especially when you are speaking about water concentration. Hypotheses abound, rather looking forward to the data. I have referenced the EI source as that is the source of the correct proposal/ratios for EI. Sorry if that offended you but thanks for making the core of your focus clear.
 
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