NH4H2PO4, CO(NH2)2, KCl


Junior Poster
Sep 15, 2009
Hi guys!

I've got these three dry ferts and I'm looking to try the EI method.

Just wondering what I do with these now? What mixes and so on... I've only found the NH4 to be under the hydro guys where as I want it for the aquarium.

What are the safe levels for the fish? How do I mix it up? How much per 500ml ?

The bags are labeled:

Nitrogen 46-0-0
Phos 11-52-0
Potash 0-0-60

I've a 37 and 65 gallon tank. Both with T5HO's @ 24Wx4 /12hr . Pressurized CO2.

I'm looking to daily dose. I just am not sure what ammounts to mix my ferts in because they're not the normal recomended ones.

PS: This is my local water supply
Town of Stettler


Plant Guru Team
Lifetime Member
Sep 23, 2007
South Florida

Could you please provide some details on the tank such as size??

EI is looking to set MINIMAL ranges and can be read about in detail here:


This thread has mult other links within it.

here is a quick one.


Read it and come back with any questions. I think it will answer most of them.

Basically determine a weekly amount of each macro. Then either divide by 7 if dosing daily, or by 3 if dosing every other day.

Than just dump that amount of fert into some water, stir and dump in tank.

The thread has ranges for most tanks. If your doesn't fit, pick the next closest. EI is ADJUSTABLE so don't think it has to be a perfect measurement.

Many folks adjust the ranges for their tank. I myself dose 2-3 times EI.

That is it basically.


Junior Poster
Sep 15, 2009
I edited the first post with the info.

I'm not sure how to mix them and if the NH4H2PO4 is going to trigger algae? Tom makes a remark about NH4+ or amonium making algae blooms?

Doing my research I am finding that
potash is muraite of potash( KCl ) ? [spelling here?]
nitrogen is urea ( CO(NH2)2 ) ?
phos us Ammonium phosphate ( NH4H2PO4) ?

as least by their x-x-x weights, that's what has come up.


Lifetime Charter Member
Lifetime Member
Jun 21, 2009
Surprise, AZ
Proverbial Cat


What Gerry said.

Potassium chloride (KCl) is no problem just doesn’t have the SO4, Tom Barr has a pretty good riff on this somewhere around here. Here I think http://www.barrreport.com/co2-aquatic-plant-fertilization/5593-k2so4-reacts-soil.html.

Ammonium phosphate (NH4H2PO4) is something we used back when the earth was young Tom Barr does a bit on it here http://www.barrreport.com/co2-aquatic-plant-fertilization/5593-k2so4-reacts-soil.html I believe not sure, if it is the right context. Be careful with this stuff.

Good old-fashioned Urea CO(NH2)2 been the basis of fertilizers since, well a long time. I think Tom Barr makes mention of it here. http://www.barrreport.com/general-plant-topics/3506-alternathera-reinekii-problem.html.

As always, there indeed exists more than one-way to skin the proverbial cat.;)

As Gerry said read up figure how to mix, being non-standard I think maybe you need to do the figuring. It is easy to burn the plants, but the plants can usually take a lot more than the critters.

Do not forget to figure micronutrients and make sure you are getting Sulfate SO4, likely via tap water, and magnesium Mg.:)



Junior Poster
Sep 15, 2009
yup... I'm still confused about how much or if I can be adding these ferts.

I'm not sure about the chemical make up... I just did a search for what's on the bag and that's what I came up with.

Is it okay to add? And how much do I add? Is adding flourish going to give me what I need for those micros?

All these dry ferts are granual and are used by farmers here, so I'm not sure if I should crush them up to disolve them?
and then, how much per how much water?


Junior Poster
Sep 16, 2009
If I were you, I would just go to aquariumfertilizer.com and buy the exact ones recommended for EI and just dose the recommended amounts instead of trying to make those ones work. I was reluctant at first, but now I realize that for less than 40 bucks I'm probably covered for the life of the tank. Way easier.

Tom Barr

Staff member
Jan 23, 2005
In smaller amounts, NH4 based ferts are okay to use, but I general suggest skilled folks that are careful to use these, and then only very sparingly.

NH4 is extremely toxic and even a little bit off can end up resulting in dead fish.
This is not about algae inducement per say, that can occur also, but generally Green water and at higher light and if the CO2 is not good, at lower light, the effect of NH4 does not appear to be as pronounced.

Green water is not that bad of an issue for many, but they tend to have a Uv sterilizer or a diatom filter, so if you have that, there's no fear of green water.

It does not harm the plants in other words.
so then it's more an issue of the fish health.

Adding 0.8ppm per day of NH4 would be the max rates, and this is none too good for fish, many plant folks have hardly any fish, or just a few etc, for them, it might not be a big deal, it is to me and the species I keep however.

Still, plants do well/excellent with a decent fish load(my source of NH4) and it's being added slow and continuously, and I get something out of the deal(I like fish), unlike most dosing schemes.

So I use NO3 which is rather non toxic, and is fine for plants.

Buy that and use that.
If you feel the need for NH4, add more fish/feed them more etc.

It's an easier organic method if you buy into the entire NH4 idea.
I don;t go that far, but use both NO3 and NH4, which tends to yield higher production of plant growth than one or the other.

That way you get the benefits of both without the trade offs of either;)
Many on line play that "either" "or" card, don't fall for that BS.

Tom Barr

Tom Barr