# 1:1 PO4:NO3 administration



## yme (Jul 25, 2005)

hello everybody.

Since recently I have a little BGA outbreak. Not really a big probem, but it raises a question.

I keep the PO4 levels around 1 mg/l and the NO3 levels around the 10-20 mg/l. The tests I use are calibrated (PO4: dupla and NO3: sera)

To keep the level up, I use two home-made dosing pumps. The amount of PO4 that is added per day is around the 0.25 mg/l. The amount of NO3 which is added daily, is also 0.25 mg/l. So I add NO3 and PO4 in a ratio of 1:1.

I wondered whether this ratio is normal and whether this (in my opinion absurb) dosing regime has caused BGA.

And what do you advice? 

Thanks!

yme

ps: I have a moderate/high light tank with pressurized CO2


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## titan97 (Feb 14, 2005)

In my tank, BGA is normally caused by a lack of water flow. The dead areas of my tank seem to acquire more of this than elsewhere. This may also be due to fish and food waste collecting in these areas. Since then, I have added more filtration and water movement to my tank, which has lowered the occurance of BGA. I also have PO4 near 1ppm and nitrates around 30ppm.

-Dustin


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## MatPat (Mar 22, 2004)

It seems BGA is also caused by low NO3 levels. You may want to try upping the amount of NO3 you add to the tank. I add about 2ppm of NO3 and 0.2 ppm of PO4 to my tanks daily. 

I don't think the ratio in which you add the two will have much of an effect unless you run out of something.


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## jerseyjay (Jan 25, 2004)

yme said:


> I keep the PO4 levels around 1 mg/l and the NO3 levels around the 10-20 mg/l.





> The amount of PO4 that is added per day is around the 0.25 mg/l. The amount of NO3 which is added daily, is also 0.25 mg/l. So I add NO3 and PO4 in a ratio of 1:1.


I prefer 10:1 ratio.

weekly addition to 75G tank

1 x tsp KNO3 twice weekly 
1/8 x tsp KH2PO4 twice weekly


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## yme (Jul 25, 2005)

thanks for the answers!

@titan97: I have already added an extra 600 l/h powerhead (in addition to the eheim professional) to avoid the problems of a lack of movement. I don´t think that´s a problem.

@MatPat:I do think I am short in PO4 and/or NO3; I have little pinholes in a random pattern (not K deficiency) in the older leaves of the elatine tiandra and hygrophila difformis. The Heteranthera zosterifolia is also showing some necrosis. I will try to up the NO3 and won´t pay any attention to the NO3 test kit, because it will most certainly give readings above the 30-40 mg/l if I increase the NO3 dosing by two. 

However, I am still a bit concerned about the ratio. You indicate that your tank is consuming 10x less PO4 than NO3. A huge difference in comparison to my 1:1 ratio. I have the feeling something is not going as it is supposed to go....

greets,

yme


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## yme (Jul 25, 2005)

Sorry Jay Luto, I didn´t read your message yet...

I totally agree with you. However, to get the 10:1 ratio in the tank, I have to add NO3 and PO4 in a 1:1 ratio. Do you think I should let go of the desired levels IN the tank and rather focuss on the amount of NO3 and PO4 which is added daily? 

greets,

yme


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## jerseyjay (Jan 25, 2004)

yme said:


> However, to get the 10:1 ratio in the tank, I have to add NO3 and PO4 in a 1:1 ratio.


???

If I followed your schedule then I would have to add 2 tsp of KNO3 and 2 tsp of KH2PO4 on weekly basis. This is definitely NOT what I'm doing now.


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## yme (Jul 25, 2005)

Jay Luto said:


> ???
> 
> If I followed your schedule then I would have to add 2 tsp of KNO3 and 2 tsp of KH2PO4 on weekly basis. This is definitely NOT what I'm doing now.


sorry about the confusion. What I mean is that I am now daily adding 0.25 mg/l PO4 and 0.25 mg/l NO3, which results approximately in a 10:1 ratio IN the tank. I think this is quite strange. Therefore I asked whether I should let go of the desired NO3 and PO4 IN the tank and just start to dose NO3 and PO4 in a 10:1 ratio.

greets,

yme


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## plantbrain (Jan 23, 2004)

Regards, 
Tom Barr

www.BarrReport.com

Regards, 
Tom Barr


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## jerseyjay (Jan 25, 2004)

plantbrain said:


> Jay, et al,
> 
> The test kit for either/both NO3 and PO4 are likely way off.
> 
> You need to add about 10X this amount of KNO3, ignore the test kit.


That is exactly what I was saying .....

10:1 ADDING ratio
7:1 ADDING ratio
or even 
5:1 ADDING ratio

is what works for me in the past and currently.

I have never tried 1:1 and have no desire ......


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## yme (Jul 25, 2005)

Tom, you are absolutely right! I based this dosing regime on testing both NO3 and PO4 extensively. Since I am aware that most testkits are not accurate I made test solutions containing 0.5-1-2-5 mg/l PO4 and 5-10-20 mg/l NO3. (dry KNO3 and H2KPO4 were weighed at a 0.001 gram accuracy in the lab where I work). I tested the solutions on different days and prepared the test solutions several times for another round of testing. The results were pretty encouraging: for PO4, one could get a general impression of the levels: moderate colouration of the water was observed at 1 mg/l. The results could be reproduced. For NO3, the same was true: especially between the 5-10 mg/l there was a high resolution. 
Based on these tests I assumed that my NO3 level is above the 10 mg/l when I add 0.25 mg/l daily . For PO4, the levels drops from 1 mg/l to 0 mg/l within 5 days when no PO4 is subsequently added and stays stable when I add 0.25 mg/l daily. 

However, as you implied, this can not be... Therefore, I must conclude that the testkits must be trown out of the window, despite the multiple accuracy tests.

Thus, I would ask you what do you suggest as a dosing regime? daily 0.25 mg/l PO4 and 2 mg/l NO3?

To give some more information about my tank:

size: 100x40x40 (cm)
pH: 6.5
KH:3
CO2: pressurized; external dupla reactor
fertilizer:2 x recommended dose of profito (dutch brand) 
light: 3x 30 watt: 13.00-23.00, 1x 30 watt 19.00-22.00

greets,

yme


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## plantbrain (Jan 23, 2004)

Regards, 
Tom Barr

www.BarrReport.com


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## yme (Jul 25, 2005)

Hi Tom, thanks for the answers!

I think, let´s put it in a nice way, that the tests are not accurate at all. (making test solutions isn´t that hard if you have a MSc. in biomedical sciences)

Yesterday, in the train back home, I did some math and indeed (of course)found that one can never reach the 40 mg/l. So, I will follow your advice and dose at least 20 mg NO3/l/week.

For the CO2, I think it is reasonably up. The pH is 6.5 (dupla electrode, calibrated last week) and the KH is 3 (more or less.......). Since a dutch friend states on his internetsite that the intake of micro´s is maximal between 6.5 and 7.2 (with different intake profiles for each nutrient), I think that it is not wise to lower the pH even more. Do you agree?

And I really keep the mega-dosing in mind!

thanks again for the answers!

yme


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## plantbrain (Jan 23, 2004)

www.BarrReport.com


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## yme (Jul 25, 2005)

I must say your view on the matter is really interesting and absolutely a way to go. 

Since I am a control freak, I would definately go for an automatic system that measures nitrate/phosphate etc and adjusts the concentration when necessary, but since I am not familiar with such a system I have to do it differently..... 
We concluded yesterday that my testkits are useless, thus it is impossible to determine the actual concentration of the previously mentioned nutrients. Therefore, it seems absolute nonsense that I use the test kits to fine tune the dosing regime. This leads to the conclusion that it is very logical to go the way you suggested.

The only thing is that I would LOVE to know the actual concentrations. It seems just weird to me that I can do in situ´s, PCRs, confocal microscopy, make transgenic animals, study proteins on a nanometer structure, etcetc, but can not determine the concentration of a simple nutrient in water. Of course, money is a problem and most likely it is like throwing your money out of the window, but at least you KNOW! I think that is just the beta-person inside me that is anxious to KNOW things and is very unhappy when that is not possible.

To go back to the CO2: I of course read about the mist-powerhead diy device that you constructed and I liked it! (not sure about the underlying scientific explanation, but that is not an issue at the moment nor do I have any knowledge about this matter) However, I think it is quite difficult to hide in a 1 meter tank and I am still not sure how you constructed the venturi-loop to the inlet of the powerhead. I hope I can find an answer somewhere on the internet!

greets,

yme


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## plantbrain (Jan 23, 2004)

Regards, 
Tom Barr

www.BarrReport.com


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## yme (Jul 25, 2005)

thanks Tom!

I will definately look into the limewood air stones! 

I looked at the price hanna photometers, but it is pretty expensive if you want the C203. But maybe it´s worth the price. I don´t know yet. If I´m rich, I will definately buy it!

After a couple of days administrating the 10x dose NO3, i.e. 20 mg/l/week, I see that my echinodorus osiris (think not that is the one, but is was sold as such) is growing larger leaves. More surprisingly, the new leaves are much more red. the stargrass looks healthier as well, but slightly yellow. On the other hand, I see clearly that long individual single stranded algae are starting to appear on the leaves of several plants. Don´t know what to think about it, but it doesn´t look good...

greets,

yme


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## plantbrain (Jan 23, 2004)

edit


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## Edward (May 25, 2004)

Hi yme

Most inorganically under dosed aquariums show some NO3 and PO4 on the test kits. However this situation is more less stagnation. It wouldn’t be the first time, if you tried a balanced complete fertilization program to see a drop in NO3 and PO4 and new healthy plant growth waiting for more fertilization.

Dose per your 160 litres aquarium daily: 
SS 2 ml
PF 4 ml
Mg 10 drops

Test for NO3 and PO4 after one and two weeks.

Edward


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## yme (Jul 25, 2005)

@Tom:

Too bad I read your post when I am already at work. I will not go home this day, so I'm afraid the removal of the algae will have to wait....

About the photometers: isn't it possible to use a general photometer that I have at the lab? I can use aneppendorf biophotometer with the following specifications:

Optical system: Absorption, single-beam photometer with reference beam 

Light source: Xenon flash lamp 
Light beam height: 8.5 mm 
Spectral range: 220 to 750 nm 
Wavelengths: Xe 230; 260; 280; 320; 562; 595 nm 
Spectral range width: 5 nm: 230 to 320 nm; 7 nm: 562 to 595 nm 
Photometric measuring range: 0,000 to 3,000 A 
Photometric accuracy: ±1% at 1 A 
Photometric precision: < 0.5% at 1 A 

However, I do not know at which wavelength the hanna photometer measures. Do you know whether it is possible to test water for nitrate and phosphate if I buy the hanna reagents and use the eppendorf biophotometer for the measurement?

@edward:

If I'm correct (I'm not because I have done the math really quick because I really should be working at the moment) you suggest that I add per day:

NO3: 1.8 mg/l
PO4: 0.1 mg/l
Mg: 1.69 mg/l (if a drop is 5 microliter)

Please correct me if I'm wrong.

For the NO3 and PO4, this is more or less what I am dosing at the moment, although I add twice the amount of phosphate. 

The Mg addition is quite more than I use to dose, which is generally 2-3 mg/l/week. I could increase that.

I tested my water for K with sodium tetraphenyl borate. The test showed that I had quite some K in my water. from the calibration I made, I estimate that I have 20 mg/l K in the water. (+/- 10 mg/l). I think this is enough. Do you agree?

greets,

yme

ps: this evening I can not respond because I don't have a computer....


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## yme (Jul 25, 2005)

oke, these are the specifications for the c203:

Central Wavelengths 420 nm / 525 nm / 575 nm / 610 nm / 460 nm 
Wavelength Accuracy +/- 2nm (full scale) 

Comlete different wavelengths.... 

greets,

yme


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## plantbrain (Jan 23, 2004)

edit


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## Edward (May 25, 2004)

160 litres

SS 2 ml
PF 4 ml
Mg 10 drops

NO3 0.94 ppm
PO4 0.10 ppm
Mg 0.10 ppm


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## plantbrain (Jan 23, 2004)

edit

Regards, 
Tom Barr

www.BarrReport.com


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## yme (Jul 25, 2005)

aha, Thanks both of you!

@edward, I indeed made some mistakes in the calculations. I was to fast and made mistakes. Thanks for correcting me!

@tom,

I found another photometer (beckman coulter du530) at the floor above my lab and I think that this photometer can measure at each desired wavelength. I will have to ask someone to confirm this though.

This means that possibly I can use this photometer. If not, I also found a german shop that sells the machine for 350 euro, the half of what it costs in The Netherlands.

I f I can use the photometer at the lab, I wondered what the recommended wavelengths are for measuring nitrate and phosphate. I couldn´t find any informatiuon about it. 

I wondered as well if you could tell me how you make the reagent needed for the measurements and which chemicals are needed.

If you could answer these questions I would really appeciate it!!!!

greets,

yme


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## plantbrain (Jan 23, 2004)

edit

Regards, 
Tom Barr

www.BarrReport.com


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## yme (Jul 25, 2005)

Tom, thanks for mentioning Hach. Using this brand I found what I needed to know. Thanks!

What surprized me was that the percentage of each compound can vary a lot between different batches! 

However, you need a lot of chemicals to make the reagents. And some of them are not on the shelf of my lab. I think it will cost a lot of money to order all the chemicals seperately. I hope it isn´t that expense (I will find out next week)

greets,

yme


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## plantbrain (Jan 23, 2004)

edit

Regards, 
Tom Barr

www.BarrReport.com


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## yme (Jul 25, 2005)

I indeed found the data by look into the manuals of hach. thanks!

I think it is worth a try to measure the levels by photospectrometry. And, if possible, I will make my own reagents.

One more thing: is the accuracy that hanna claims for NO3 and PO4 measurements (using their reagents) true?

greets,

yme


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## plantbrain (Jan 23, 2004)

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## yme (Jul 25, 2005)

> I collect samples and freeze them asap or otherwise preserve them and then test a bunch all at once.


very smart indeed!! I will do the same thing!

one more thing, can you make the reference samples by mixing osmosis water with the desired amount of NO3/PO4 or do you need to add other salts as well to prevent non-presentative readouts from your reference samples?

So, now I think it´s time to introduce myself on barrreport!

greets,

yme


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## plantbrain (Jan 23, 2004)

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## yme (Jul 25, 2005)

Thanks! I will make the solutions as you suggest. For the volumetric flasks, I will borrow some from my lab.

greets,

yme

ps: thanks for helping me again!


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## BryceM (Nov 6, 2005)

Very nice thread. It becomes increasingly obvious to me that the science and math behind all this really do make EI a reasonable choice. It removes most of the guesswork and is pretty idiot-proof.

I had one major issue with it though. I got into trouble with my NO3 levels and had sick fish and horrible green dust. I was overestimating my light (and therefore uptake levels) and maybe underestimating the WC% I did each week. I'm using a finely powdered KNO3 and don't know the gram/tsp factor for it. I suspect my relatively large fish load had something to do with the NO3 levels too. After about a month my NO3 was >80 ppm(maybe more, I didn't keep diluting to get an accurate read in the Lamotte range).

There is such thing as adding too much. Even 50% WC's don't help at some point. For this reason I think it's reasonable to do SOME testing to check the progress of things.


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## plantbrain (Jan 23, 2004)

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## BryceM (Nov 6, 2005)

Tom,

Speaking of a better idiot...... well, um, yeah, apparently I did need a test kit. This is where your experience is certainly helping you even without realizing it. For me, I was working my way through the newB thing with every algae problem imaginable. I wasn't willing to be patient enough to be scientific about it - change 1 thing at a time, wait 1-2 weeks to observe the change, etc.

It was enormously helpful to do a search for optimum nutrient values and do some spot checks to see if I was even in the ballpark. It turns out I wasn't, and didn't have the background to know what was wrong. I'm learning how to read various deficiencies by watching the plants and am much better at it than I was a few months ago, but a few checks with the Lamotte kits really helped get things to a happy place faster. Once I got it right within a couple of weeks everything looked incredible.

Currently I'm kind of using a marriage of ideas. I'm doing the EI weekly 50% WC's to reset everything, and smaller dosing of ferts keep NO3 and PO4 within a range of what I think is optimum (15-30, 1.5-3.0). From my few months of anecdotal observation I agree with you 100% on several points:

- proper and consistent CO2 is absolutely crucial
- it's better to be nutrient rich than nutrient poor (_to a point_)
- light should be the limiting factor
- watching plants is better than watching test kits _once you know what you're looking for_

As simple as all this sounds, it surely became clear only with a great deal of testing and observation. It represents an enormous leap forward in the ability of many people to keep nice tanks.

I'm still wondering about the following:

- Why does the algae 'go away' once the plants are happy? All the stuff the algae needs to thrive is still there in great abundance. Nobody has ever been able to explain this to me.

- I'm not a scientifically naive type of person and I had issues following the recipe. I'm sure other hobbyists are frustrated at times too, without understanding why EI isn't working for them. They lack the experience to make the observations that would get them out of trouble. People try to raise plants under an enormous variety of conditions (lighting, fish load, plant density) and surely there needs to be some way to dial it in to their particular system. I finally got there, but it wasn't without some thought and moderately accurate water testing.


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## plantbrain (Jan 23, 2004)

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## Edward (May 25, 2004)

Hi
There is something we as plant growers are forgetting or ignoring. It is the fish health. The N, P and Trace Elements in our aquariums are toxic to fish, snails and shrimps. 


Edward


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## plantbrain (Jan 23, 2004)

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