DRY FERT HOW TO: PPS Pro with Calcium Nitrate instead of Potassium nitrate

I started out using pre-mixed ferts as they are easily available and ready to be used. And financially, it does not make a big impact when you have just one tank.

However, when you progress in this hobby, you will most likely ended up with a handful of planted aquariums in your home. And as you gain more confident and interest in the hobby so does the size of your aquarium.

When you progress into multiple aquariums or into the territory of large aquarium like a 75 gallon, buying pre-mixed ferts becomes a financial burden. You will find yourself buying larger quantity of of ferts to enjoy more savings. But it will come to a point whereby buying in bulk will still hurt.

This is usually the signal for most to search for “How to dose dry ferts”.

There are literally thousands of very useful information online, mostly from forums. Again! No single place to give a direct instructions to simply follow. They all provided theories, methods, and explanation, but no simple instructions.

What you will need to buy

In a lot of countries Potassium Nitrate (KNO3) is a control substance and are not available as powder form to be sold openly. You may find some shops selling 5% KNO3 solution but I will show you how you can substitute KNO3 with Calcium Nitrate, which is much widely available.

Shopping List

Potassium SulphateK2SO4
Calcium NitrateCa(NO3)2.4H2O
Potassium Dihydrogen phosphateKH2PO4
Epsom Salt/Magnesium SulphateMgSO4
Seachem FlourishMicro nutrients
EDTA Fe (13%)/DTPA (7%)Fe
Seachem Flourish IronFE ferrous iron gluconate
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Digital weighing scaleTo measure the chemicals weightGet it here> USD3.00 Free Shipping
BeakerTo measure water volumeGet it here> USD1.50
2x 600ml bottlesTo contain the mixed ferts

I will leave you to do your own reading about how the above chemicals will provide NPK and the micro nutrients.

Noted about FE dosing

If you can’t get your hands on FE in EDTA 13% or DTPA 7% form, you can just grab a bottle of Seachem Iron or other equivalent.

EDTA chelated 13% is meant for water with pH lower than 6. Water at more than pH 6 most of the iron will not be absorbed. Also it is best for soft water.

DTPA chelated 7% is best for water up to a pH value of 7.5. It is also less reactive with calcium rich water.

Where to buy

The chemicals can be found in any home gardening stores. These are common fertilisers used by gardening as well as hydroponics.

When buying online, please choose fertiliser grade. Lab or science grade can be very expensive.

Singapore Readers

For dry ferts you can get it online from ECO CITY. Click below to go directly to the links to the individual ferts

Potassium SulphateLink
Calcium NitrateLink
Potassium Dihydrogen phosphateLink
Epsom Salt/Magnesium SulphateLink

For Epson Salt you can get it from any pharmacy.

For the bottles, I got it from Daiso! $2 each!

For the digital scale, you can get it from AliExpress just USD4 with free shipping!!! WTF?! In the US and can’t wait? Try Amazon USD8.


There are again a lot of types of dosing methods but I will touch the PPS Pro for now. It is a leaner methods than EI methods.

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You will need two bottles for the dry ferts. This is a draw back when you use Calcium Nitrate instead of Potassium Nitrate.

When you mix Potassium Sulfate and Calcium Nitrate there will be a chemical reaction which will result in a white precipitation (Calcium Sulphate). It is fine to dose into your aquarium but may be unsighty.

Cap on right is when you mix everything in one bottle – White precipitation (Calcium Sulphate)

So you need to prepare a separate bottle for Calcium Nitrate.

Bottle #1

Potassium SulphateK2SO429.3g
Potassium Dihydrogen PhosphateKH2PO42.7g
Epsom SaltMgSO419.2g
Distilled Water (tap water is fine)H2O500ml

Bottle #2

Calcium NitrateCa(NO3)2.4H2O36g
Distilled Water (tap water is fine)

Bottle #3

EDTA Fe (13%) | DTPA Fe (7%) | DTPA Fe (10%)14.56g | 27g | 19g
Distilled Water (tap water is fine)500ml

That’s it!

If you have a 10 gallon tank, each dose is 1ml. It will last you 16 months!

Dosing Amount

It is very simple. The base amount are as follows,

Bottle #1Bottle #2Bottle #3Flourish
1 gallon0.1ml0.1ml0.1ml0.083ml

Example, if you have a 75 gallon tank, then multiply 75 to the base amount. If you have a 5 gallon then just multiply the base amount by 5.

Bottle #1
Bottle #2
Bottle #3
3 times per week
3 times per week
5 gallon0.5ml0.5ml0.5ml 0.42ml
10 gallon1ml1ml1ml0.83ml
55 gallon5.5ml5.5ml5.5ml4.57ml
These bottles are meant for detergent but are just great for containing your ferts.

Dosing Frequency

Bottle #1 (Macro)Daily
Bottle #2 (Macro)Daily
Bottle #3 (micro)3 times weekly (alternate with Micro)
Seachem Flourish (Micro)3 times weekly (alternate with Bottle #3)
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Dosing Adjustment

The PPS Pro is somewhat in the lean spectrum of dosing regimes. The standard dose amount is for lightly planted tank or for tank with low lighting.

If you have heavily planted tank please double the dosage for Macro. If you have medium or high lights please double or triple the dosage for Macro.

In essence, the PPS Pro is a lean EI dosing regime.

That’s it! Have fun!