so, what exactly do you want?

I think he’s after the fertilizer numbers N/P/K for his media. Usually these are given as percentage by mass, for instance a 20-10-5 fertilizer is 20% nitrogen, 10% phosphorous and 5% potassium. These are often used for inorganic fertilizers for which the calculation of masses is straightforward from the formulation of the compounds, though elemental analysis of a complex organic fertilizer mix also allows assigning fertilizer numbers. We’ve no idea what’s in the media mix — if it is a defined medium, then in principle the fertilizer numbers could be calculated without doing additional analytical chem. Is there no mass percentage of N, P and K on the packaging?

On re-reading the original post I now suspect he’s like to avoid the preformulated media mix and perhaps make his own. That can be done, but it could be a tough project to match the media mix composition if you are not familiar with chemistry calculations.