Hi all,

It is given as 5 ml per 50 liters.

That makes it really easy,

** the percentage on the bottle is the same as the ppm of each nutrient supplied**, because the various dilutions are all factors of 10 and cancel one another out.

TSN is ammonium/urea based for its source of nitrogen, so in getting the [NO3] ppm above we have assumed all the N is converted to NO3

Yes, so we have nitrogen (N) and we want to convert that to a nitrate (NO3-) value, bearing in mind

@Zeus.'s comments. We need to know the percentage of N in NO3, and to do this we need to know the Relative Molecular Mass (RMM) of NO3- and Atomic Mass (RAM) of oxygen (O) and nitrogen (N). In this case "16" for oxygen and "14" for nitrogen so we have 14 + (3 * 16) = 62 and then we can divide 62/14 = 4.43 and then multiply 1.34 * 4.43 = 5.93 ppm NO3 in 50 litre.

**Calculation bit**
You don't need this bit anymore, but along with the RAM values of the elements, these are the underpinnings of the IFC Aquarium Fert. calculator.

The spreadsheet is incredibly useful because it <"

automates the whole process">, and makes <"

value for money comparisons"> etc much more accessible, where you have a less straight forward calculation.

N 1.34%

P 0.1%

Mg 0.39%

K 1.03% ..........

I'll go through the calculation for potassium (K), but exactly the same process applies to each of the other nutrients.
You have 5 mL of TSN with 1.03% K, first we need to convert 1.03% to a decimal, so that equates to (5 * 0.0103) and

**0.0515 g of K**.

At this point we have to assume that we are dealing with water, rather than a a dilute solution, and that 1 mL weigh 1 gram, and that ppm is equivalent to milligrams / litre or micrograms / gram, so we have added 51.5 mg of K to 50 litres of water <"

and mg / L is the same unit as ppm">.
That means we have 51.5 / 50 = 1.03 ppm K.

To check divide 1.24 by 6 (0.207) and multiply 0.207 by 5 and you should get ~ 1.03

& another one for luck,

Magnesium (Mg) this time: 5 * 0.0039 = 0.0195 and 19.5 / 50 = 0.39 ppm Mg

cheers Darrel