Potassium nitrate vs. nitrate from fish waste and ammonia?

cubequeen · Apr 21, 2017

I'm having trouble getting my plants to grow despite dosing with everything except any nitrate and know at one time when I was accidentally over-dosing with potassium nitrate I was having prolific plant growth. As I say, it was an accident and I have been reluctant to add any potassium nitrate to my tank as the nitrates are already sort-of high.

So-o-o-o-o, I started wondering. Is the nitrate that builds up in the tank through the normal nitrogen cycle different from dosing with potassium nitrate? If potassium nitrate is POTASSIUM nitrate, what kind of nitrate is produced by the nitrogen cycle? Is it ammonia nitrate or ammonium nitrate since it derives from the ammonia from fish waste, etc.? If so, would it be advisable to do water changes to reduce the ammonium nitrate or whatever it is for the sake of the fish, yet dose with potassium nitrate for the sake of the plants, even though this practice would keep "nitrate" high as detected by nitrate tests? In other words, is potassium nitrate less toxic than the nitrate from fish waste?

rajkm · Apr 21, 2017

Potassium Nitrate (KNO3) and Ammonium Nitrate (NH4NO3) are fertilizer salts. When you add these in water they break down into individual chemicals or bind with others to form other compounds.

Nitrate cycle is Ammonia (NH4)->Nitrite(NO2)->Nitrate(NO3).

If you think you have enough nitrates then all you might need is Potassium (you can use potassium sulphate) and Traces (Flourish or CSM+B).

Plants need more than Nitrate to survive. Potassium, Phosphates, Iron, Calcium, Magnesium, and other traces.

Pikez · Apr 21, 2017

cubequeen said:
I'm having trouble getting my plants to grow despite dosing with everything except any nitrate and know at one time when I was accidentally over-dosing with potassium nitrate I was having prolific plant growth. As I say, it was an accident and I have been reluctant to add any potassium nitrate to my tank as the nitrates are already sort-of high.

So-o-o-o-o, I started wondering. Is the nitrate that builds up in the tank through the normal nitrogen cycle different from dosing with potassium nitrate? If potassium nitrate is POTASSIUM nitrate, what kind of nitrate is produced by the nitrogen cycle? Is it ammonia nitrate or ammonium nitrate since it derives from the ammonia from fish waste, etc.? If so, would it be advisable to do water changes to reduce the ammonium nitrate or whatever it is for the sake of the fish, yet dose with potassium nitrate for the sake of the plants, even though this practice would keep "nitrate" high as detected by nitrate tests? In other words, is potassium nitrate less toxic than the nitrate from fish waste?

Your answer is in your first paragraph. Your second paragraph suggests you've overthought this and it's taken you astray.

Please accidentally 'overdose' with potassium nitrate again.

And see what happens. Assuming you have enough light, CO2 and all the other stuff plants need, you should see a burst of growth. Until you run out of something else. Then plant growth will slow down again and you can worry about that later. But for now, accidentally slip some potassium nitrate into your tank. It won't harm the fish and the plants will love it.

Amanda Adkins · Jul 18, 2017

Almost all living things on this earth need the same nutrients. If you were only to consume nitrates which are the base of proteins you would be malnourished fairly quickly. Plants need potassium and calcium for cell structure; phosphates for reproduction of cells; chloride for photosynthesis; magnesium for root and blossom development as well as nitrates in balance.

Greggz · Jul 18, 2017

cubequeen said:
So-o-o-o-o, I started wondering. Is the nitrate that builds up in the tank through the normal nitrogen cycle different from dosing with potassium nitrate?

That's a great question. One I have asked myself on many occasions.

I have no scientific reason for my opinion, but I tend to agree with Pikez above. In my 120G heavily stocked Rainbow tank, it would appear fish waste/food would supply all the N & P plants could use. The N & P measurements appear to confirm that as well.

But the thing is, every time I test that theory, the plants suffer when I stop dosing. Start dosing, and plants are happy again. Readings do seem high, but so what if fish and plants are all thriving? So in my mind, based on observations of my own tank, I tend to believe there is a difference in the way plants process each.

VaughnH · Jul 18, 2017

My experience is that most of the aquatic plants I have grown have not been perfect. Some of them sometimes have holes in the leaves, some sometimes lose leaves when they rot, some have a bit of yellow on some leaves, etc. But, as long as they are all growing well, looking good to me, I never try to adjust conditions to achieve perfection. The few times I have altered my fertilizing looking for better results I end up with more problems than I started with. So, I'm a fan of the EI dosing method.

I have read many forum threads about the problems that overdosing causes, but I haven't been inspired to seek perfection. If the fish are healthy, and the plants grow well, I consider my fertilizing to be just right. But, I do appreciate those who have been able to fine tune their dosing and get beauty contest winning aquascapes.

KeeperOfASilentWorld · Sep 28, 2017

cubequeen said:
I'm having trouble getting my plants to grow despite dosing with everything except any nitrate and know at one time when I was accidentally over-dosing with potassium nitrate I was having prolific plant growth. As I say, it was an accident and I have been reluctant to add any potassium nitrate to my tank as the nitrates are already sort-of high.

So-o-o-o-o, I started wondering. Is the nitrate that builds up in the tank through the normal nitrogen cycle different from dosing with potassium nitrate? If potassium nitrate is POTASSIUM nitrate, what kind of nitrate is produced by the nitrogen cycle? Is it ammonia nitrate or ammonium nitrate since it derives from the ammonia from fish waste, etc.? If so, would it be advisable to do water changes to reduce the ammonium nitrate or whatever it is for the sake of the fish, yet dose with potassium nitrate for the sake of the plants, even though this practice would keep "nitrate" high as detected by nitrate tests? In other words, is potassium nitrate less toxic than the nitrate from fish waste?

Tom Barr explains this specific subject very thoroughly in his Nitrogen and in his Fish Waste article. Why not give them both a read

tiger15 · Dec 26, 2017

Greggz said:
That's a great question. One I have asked myself on many occasions.

I have no scientific reason for my opinion, but I tend to agree with Pikez above. In my 120G heavily stocked Rainbow tank, it would appear fish waste/food would supply all the N & P plants could use. The N & P measurements appear to confirm that as well.

But the thing is, every time I test that theory, the plants suffer when I stop dosing. Start dosing, and plants are happy again. Readings do seem high, but so what if fish and plants are all thriving? So in my mind, based on observations of my own tank, I tend to believe there is a difference in the way plants process each.

After reading your journal, I believe in your claim. But could there be difference in response between low versus high light plants. Your plants are heavy feeding, fast growing stem plants that even a momentarily drop in nutrients may impact growth. I came across many low light systems that seem to thrive with no dosing.

KeeperOfASilentWorld said:
Tom Barr explains this specific subject very thoroughly in his Nitrogen and in his Fish Waste article. Why not give them both a read

Where is the link to Tom's article? Tom published so extensively that it's not easy to find the relevant article.

KeeperOfASilentWorld · Dec 27, 2017

tiger15 said:
After reading your journal, I believe in your claim. But could there be difference in response between low versus high light plants. Your plants are heavy feeding, fast growing stem plants that even a momentarily drop in nutrients may impact growth. I came across many low light systems that seem to thrive with no dosing.

Where is the link to Tom's article? Tom published so extensively that it's not easy to find the relevant article.

Here you go

https://barrreport.com/articles/nitrogen-cycling-in-planted-aquariums-volume-1-issue-6-june-2005.20/

https://barrreport.com/articles/fish-waste-and-macrophytes-volume-3-issue-2-march-2007.24/

I advise you to read all of his articles which are under the articles section of barrreport.com. They could not be any more informative.

tiger15 · Dec 28, 2017

Thanks for the links. But it only allow men to read the first page, not the full article.

I have a hypothesis that it may be the fluctuation of the nitrate levels, not the type of nitrate, that impact plant growth. A 50% WC recommended by EI can lead to gyration of nitrate levels if dosing of nitrate is skipped. Plants use energy to uptake nitrogen, and gyration of nitrate levels, similar to gyration of CO2, can confuse and impact plant growth. This may explain why EI works because it recommends daily or every other day dosing to keep the nutrient levels steady. One test of the hypothesis is to do daily small WC, instead of large weekly WC, to see if skipping N dosing in heavily stocked tanks works.

Swissal · Dec 29, 2017

Regarding only seeing the fist page, I had the same problem when trying to access the articles over my IPad. I went over to a windows PC and it worked fine.

Potassium nitrate vs. nitrate from fish waste and ammonia?

cubequeen

Subscriber

rajkm

Article Editor

Pikez

Rotala Killer!

Amanda Adkins

aquariumfertilizer.com

Greggz

Lifetime Members

VaughnH

Lifetime Charter Member

KeeperOfASilentWorld

Member

tiger15

Member

KeeperOfASilentWorld

Member

tiger15

Member

Swissal

Lifetime Members