The first synthetic hydroponic
nutrient was first developed in 1859, hydroponics or water culture has been around since the 1500s. that's before there were synthetic and chemical fertilizers.
That's why I use the words synthetic
nutrients and organic nutrients.
The difference is simply that organic nutrients, don't contain any harsh chemicals that are harmful to the environment. Organic nutrients allow a slow release of nutrients, enabling the plants to have a consistent source of food, and encourage healthy growth, of naturally occurring beneficial organisms (which aren't in synthetic nutrients). Which means you cant chemically burn up your plants.
I don't have a ppm meter and have never used one, I use a feeding schedule as recommend by the product brand, and it seems to work very well. All I check is the ph in my system. Growing hydroponically with totally organic nutrients is actually easier and cheaper than growing hydroponically with man-made chemicals by eliminating the need to balance different nutrient levels with ppm and pH in the water reservoir eliminates most of the problems associated with hydroponic growing.