# Alternates to KNO3 for Nitrate Dosing



## aquaverde (Feb 9, 2004)

I'm wondering what else other than KNO3 anyone of you may be using for nitrate dosing, and where you obtain it. I would like to stock an alternate to the potassium salt most of us use so that I can have more leeway with potassium levels in my tanks.


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## gpodio (Feb 4, 2004)

I've used Flourish nitrogen in the past, gets expensive though. If you are jumping on the "low K" wagon, then I don't think you will ever have problems if your only source of K is from KNO3 and what little K is in your trace mix. Increasing the fish load would increase nitrogen levels and therefore you would use less KNO3.

Although I have never tried it, NH4+ may be one alternative, if dosed correctly it should be prefered by the plants and removed or converted rather quickly by plants and bacteria. What is converted by bacteria and not consumed by plants would then become nitrate which in turn goes back to the plants should they run out of NH4+.... Although you'd have to dose very small amounts throughout the day to prevent levels becoming toxic to fish. ...works in theory right? ;-) 

Urea is another nitrogen source however both of these alternatives could possibly cause some issues with algae growth. I think I'd stick to KNO3 personally. Others might have better alternatives.

Giancarlo Podio


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## JLudwig (Feb 16, 2004)

gpodio said:


> Urea is another nitrogen source however both of these alternatives could possibly cause some issues with algae growth. I think I'd stick to KNO3 personally. Others might have better alternatives.


Check out:
http://www.extension.umn.edu/distribution/cropsystems/DC0636.html

Urea is basically NH4+, I think this reaction is pretty fast in our warm bacteria filled tanks. A quick lesson in hand waving redox chemistry might be in order here...

NH4 and Urea are prone to oxidation by oxygen. This means they are a "fuel" as they are very rich in electrons - they pack a whallop so to speak. NO3 is the leftover after the electron energy has been extracted by aerobic bacteria...

What does this mean practically? Well, nitrate is relatively a low grade of nitrogen. Because of this, it is unlikely to cause excessive algae growth, especially in the presence of healthy plants. NH4 and Urea however can cause explosive growths of algae very quickly.

If you're going to add urea or NH3 you need to deliver it where the algae aint, this basically means via substrate additions. You can do this in the form of Jobes spike, Osmocote, or in a more subtle way... it may be possible that in a deep enough substrate which is anaerobic to run the biofiltration reaction in reverse, that is convert NO3- back to NH4+...

Jeff


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## plantbrain (Jan 23, 2004)

Well you likely have soft tap water in NY, so Ca(NO3)2 would work just dandy and add some MgSO4 baking soda and that would take care of a lot for you fast. 

Calcium nitrate has been used by a few folks mainly for the Ca and the ease of getting it to dissolve vs CaCO3. 

I know of no upper limit on Ca levels, I've been to 440ppm.
As far as K+, I went well above 50ppm recently. Erik said he went to 100ppm K and we both grow Ammannia and funny odd plants etc.
I know the high K+ thing is a bandwagon, but whatever works as long as the K+ is not limiting.

Using KNO3 alone is enough to take care of both needs though so this upper range in the 30ppm or higher is not needed but it will not hurt, if it was as bad as some folks say, folks would have been itching and complaining for the last 10 years or so.

So some said it was with only certain plants, well, I have those plants.
I grow them just fine. I added more K+ a few weeks to see if it occurred like these folks said.

No change for me. I have not observed anyone's high K+ exhibiting these symtoms in person, nor my own over many years. The K+ is there, all the other things needed for good plant growth, but I don't get the stunting.

I have found nothing in the research either suggesting this in aquatic plants.

Regards, 
Tom Barr


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## aquaverde (Feb 9, 2004)

Well, I'm not ready yet to dose high octane ammonium. If I do get to the place where I want to play with it, it will be in a tank that I don't mind experimenting with (preferably fishless). I was interested in being able to dose nitrate independently of potassium. I found a post by Paul K. where he had used calcium nitrate, but there were complications because it is hygroscopic. I have yet to hear anyone mention any other nitrate salt.

Giancarlo is probably right, and it's not going to really be an issue. Anyway, it doesn't look like there's much of anything easily available.


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## aquaverde (Feb 9, 2004)

plantbrain said:


> Well you likely have soft tap water in NY, so Ca(NO3)2 would work just dandy and add some MgSO4 baking soda and that would take care of a lot for you fast.


Very soft, probably rivals San Fran water.

As a relative newbie, I'd like as much flexibility as possible as I develop something of a dosing method. The K+ thing may be a wash, or more likely, may have little bearing on water like mine. I'm looking for some tools for my toolbag- see what works best for my tanks.



> Calcium nitrate has been used by a few folks mainly for the Ca and the ease of getting it to dissolve vs CaCO3.


From the sound of it, it's difficult to keep the stuff _out_ of solution. It will make its own!

This may sound a little heretical, but I like the idea of being able to adjust individual substances and maybe stretch the time between big water changes. When you add any salt, obviously you add two substances to the water when you may not want but one. Maintaining nitrate at a target over a couple of weeks without accumulating high doses of K+ or something else sounds like it has some value to me. I might just be all wet, though, as I doubt I'm going to discover over a few months something the oldtimers like yourself have been dealing with for decades. If ammonium weren't such a problem, it would be the answer to what I'm looking for. I can't hang over the tank with an eyedropper every hour, though.

Where would be some places to look for cacium nitrate?


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## gpodio (Feb 4, 2004)

plantbrain said:


> I know of no upper limit on Ca levels, I've been to 440ppm.
> As far as K+, I went well above 50ppm recently. Erik said he went to 100ppm K and we both grow Ammannia and funny odd plants etc.
> I know the high K+ thing is a bandwagon, but whatever works as long as the K+ is not limiting.


Tom,

I've been following the K+ threads lately but have been reluctant to post any opinions about it. Mostly because the people who are warning us about K levels know a lot more than I do about chemistry so I take their suggestions rather seriously. However last year I spent a lot of time raising and lowering levels of individual elements to see the effects it would have on my tanks. In the month that I played around with potassium, I didn't notice any problems in plant growth when I dosed 20-30ppm each week. I did however have signs of calcium deficiency in my A. Gracilis, before, during and after the potassium tests. I eventually solved it by adding calcium and magnesium tablets in the substrate. My E. Stellata shows signs of calcium deficiency when my Flourish Tabs are all consumed for example, but it's hard to say if it's actually calcium or just a nutrient shortage of some other kind.

Either way however, I have never kept a potassium level of 30ppm as some suggest, I've always dosed around 5ppm following water changes and another 5ppm in the daily doser distributed throughout the week. Other K sources are obviously KNO3 and my trace mix. So I guess I'm somewhere in between the two "bandwagons".

I'd like to test this again for longer than a month, perhaps that will give me different results. Either way, what's your take on this? And what, if it's not potassium "overdose", could be causing such signs of deficiency in peoples tanks when K levels were raised?

Regards
Giancarlo Podio


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## plantbrain (Jan 23, 2004)

Perhaps more traces(and not just Fe) and when you add the NO3, PO4, K+, even GH, this puts a larger demand on the traces. 

Still, folks would have seen this more before this. But few folks had ES back then, now everyone has it. 

It grows well for me, at 20ppm but I have not tried high K+ on it but I know many that have. It's a funny plant but some of the nicer looking plants have been raised in higher K+ levels. 

My advice would be to add more NO3, more traces, maybe some Ca/Mg and then see if the high K+ has much effect. 
I suspect it will not.

I think some folks have not been keeping some other nutrients, parameter etc in line.

Some approach things conservatively, too much, or some go the other way and over dose.
Some mix these two together.

Some things are not talked about such as flow rates, plant biomass, filter size, and other non Nutrient issues and this can account for some variability. 

I don't know what those folks are doing, but I know what I am doing and what the tanks I've seen in person exhibit.

But this is neither here nor there, I'm mildly interested if it was a real effect I could duplicate, but it's not, so I'm less inclined to do much further work on it after trying the Ammannia out here recently.

So if folks simply add KNO3 and not add any K2SO4 unless they are getting a lot NO3 from the tap or the fish load/low light etc, then 
KNO3 by itself for most of the folks with issues should have no problems.

Main thing is to have some excess K, 10ppm is excess K relative to NO3 at 10ppm.

Ratio may help some but the main issue is keeping these nuitrients from becoming limiting. We dose and do water changes often so th3is ratio does not really mean much until things get down low and become limiting or if you try and run your tank very lean, not a good idea IME/IMO. 

Some folks might try to add 3ppm daily of NO3/K+ and 0.3ppm of PO4, while I might add 10ppm NO3 every 3 days etc or some might enrich the substrate with something and add less trace, NO3/PO4 etc.

You can skin this cat a number of ways but if things go to zero for long, the plant will suffer.

Adding a bit more and keeping it richer generally helps, NO3 stunting occurs more often than some folks are considering also I believe, especially those that are trying to get more red colors through NO3 limitations.

I and other have been down that road already.

Regards, 
Tom Barr


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