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Discussion Starter · #1 ·
I'm working on a spread sheet for making DIY hydroponics ferts for emersed people.

Can someone (Edward ..hint hint;)) check these numbers

Suppose I add 100grams (just a number for the sake of calculations) of the following and add enough water to make 1000mL solution (assuming 1g/cc mixed):
Calcium Carbonate
Plantex CSM+B

This will result in the following concentrations:
N 4.30%
K 11.60%
K (K2O) 10.89%
P 2.28%
P (P2O5) 5.23%
Fe 0.65%
S 5.33%
Ca 4.01%
Mg 2.16%
B 0.118%
Mn 0.187%
Mo 0.005%
Zn 0.037%
Cu 0.009%

Is my math correct here?


193 Posts
I did the first calculation for KNO3 and got something different. Sorry I can't go through and check everything, I'll just show you how I did it with KNO3.

Molar mass KN03 = 101.1g
Molar mass N = 14.0g

100g KNO3 x (14.0g/101.1g) = 13.8g N = 13,800 mg N
1000mL = 1L
13,800mg/L = 13,800 ppm N

By definition I believe 1% = 10,000ppm. 10% = 100,000ppm. 0.1% = 1,000ppm and so on.

Therefore the percentage of nitrogen in solution is 1.38%.

I'm sure this is right but someone should verify it.

Premium Member
2,036 Posts
Before we go any further, I would recommend a different hydroponic solution using chemical compounds that are easier to obtain and mix.

CaNO3 150.0 g
K2SO4 11.5 g
KNO3 52.2 g
KH2PO4 34.8 g
MgSO4 112.0 g
TE 10.0 g

( TE Plant-Prod® Chelated Micronutrient Mix or Plantex CSM+B )

Preferably storing CaNO3 and MgSO4 separately while dry.

When mixed with water, use TDS Total Dissolved Solids meter to create concentration of 2500 uS micro Siemens for large plants or 600 - 800 uS for emersed aquatic plants. Approximately 1 tbs for large plants or 1 tsp for aquatic plants, per 10 liters. Change water every 2 weeks.

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