What is KNO3 and KH2PO4?

[|squee|]

KNO3 is potassium nitrate
KH2PO4 is potassium di-hydrogen phosphate

These two chemicals are often bought in powder form (white powder), and are a cheap means of liquid fertilisation for many planted tanks. Dosed in a planted tank, they provide potassium, nitrogen and phosphorous; the three nutrients needed by plants in large amounts.

Users of these chemicals are usually followers of the Estimative Index by Tom Barr, or a personal version of it, or simply want to supplement their main fertilisation routine. Read about it here, or read the less technical version.

Where to buy?
In Singapore, you can buy these two chemicals at LFSes(local fish shops) like Nature Aquarium opposite Thomson Medical Centre*. KNO3 can also be found at plant nurseries (they use it as a stump remover or a fertiliser). KH2PO4 can be substituted with Fleet Enema (the bowel movement inducer sold at pharmacies).

How to dose?
Enter in the amount in ml or teaspoons and the calculator will figure it out for you. Pretty straightforward: APC's Fertiliator.

[Betta Almighty]

Hey Squee,

Ive got the Fleet Enema and im wondering how much should i dose. Cant seem to find out from the APC's Fertiliator. Need some guidance here.

Thanks

[|squee|]

APC's fertiliator has it! Under "Phoshpate PO4", "Fleet Enema"

[FishFan]

Hi Terence,

I'm using Chuck's Calculator. Any idea how it compares with the APC Calculator? Thanks!

[|squee|]

I preferred the modern looks of APC's calculator. However of course... the calculations should be the same, or updated according to newer product compositions.

[troyz]

Thanks Terence for putting up on the sticky thread...it really helps after reading this thread...currently using this 2 KNO3 N KH2PO4... my plants grow like weeds

[hebi]

may i ask how much would be enough of each KNO3 and KH2PO4 in my 3ftx1ftx1ft tank?

[kck]

Need to add both to react to get the NPK for the plants?

[|squee|]

Because KNO3 provides potassium and nitrogen, and KH2PO4 provides potassium and phosphate, you add both so that your NPK needs are satisfied.

[Blankies]

How do we mix it up?

Mix the 2 powder and add water?

Cant see the links. they are broken Thanks in advance

[Patrick76]

I saw a range of figure below the individual chemical. For example, NO3 is 10-20. Is 20 the maximum dosage based on per week basis?

[|squee|]

You mean in APC's Fertilator?

Those are just guidelines. Tom Barr's Estimative Index also recommends a range of values that you can use. He recommends NO3 from 5ppm to 30ppm if I remember correctly. They aren't per-week basis, they are levels mantained in your tank (if you know what I mean).

BTW, it's impossible to find KNO3 nowadays thanks to terrorism.

[Patrick76]

Yes, I am referring to APC's Fertilator.

The range is pretty wide. He mentioned that we can dose it once a week. If we need to maintain a level of at least 5 ppm. Then we need to dose in at least 35 ppm every week. Likewise for 30 ppm, it will be 210 ppm weekly. How do you guys make use of the Fertilator?

Oh...then how you guys get your supply of KNO3?

[|squee|]

I don't understand what you mean How did you get those numbers?

[felix_fx2]

Singapore cannot sell kno3.
So the answer is nowhere, some are using the replacements.

[Patrick76]

Sorry, maybe I should rephrase my question.....What Alternative are you guy using?

[Shadow]

Yes, I am referring to APC's Fertilator.

The range is pretty wide. He mentioned that we can dose it once a week. If we need to maintain a level of at least 5 ppm. Then we need to dose in at least 35 ppm every week. Likewise for 30 ppm, it will be 210 ppm weekly. How do you guys make use of the Fertilator?

Oh...then how you guys get your supply of KNO3?

Normally you want to maintain 30ppm per week

[|squee|]

Sorry, maybe I should rephrase my question.....What Alternative are you guy using?

I'm using my old stock. Right now what people use is calcium nitrate I think?

[dc88]

For my case I add 15ppm worth of NO3 for the whole week (over 3 times : Mon, Wed, Fri, 5ppm each time), and I sampled check the tank water once a while normally it started with 5ppm after a 50% water change, and at the end of the week it is around 10ppm. So my plant probably use up 10ppm of it plus other N source from the fish food.

[dc88]

Oh, and is using calcium nitrate. Seachem Nitrogen can also but more expansive.