Well plants can't consume organic matter. Has to be broken down by living things in the soil. Like protozoa and microorganisms and shit like that.
That's my understanding of soil.
Plants put waste into the water as well.
Unless your ratio is spot on levels will sway into higher concentrations of the nutrients its eating less of over time.
So week 1 you have a higher concentration of a nutrient its using less of and since you're mixing to a set EC you're feeding less on the water add back.
So its getting less of the nutrients it needs. Furthermore its getting another full dose of what its needing less of. Week 2 your ratio of the nutrient its using less of vs more of is still increasing.
Go on long enough an excess of certain nutrients locks out others.
If cost is a concern buy cheaper nutrients. An idea would be the nutrients in their pure dry form. Or a hi-k (5-11-26 I use. Jacks makes one as well) with micros and calcium nitrate, monopotassium phosphate, magnesium sulfate (Epsom salts)
Ya get it?
