Nutrients are the most overrated and misunderstood part of growing. simply all one need do is supply adequate amounts of all the required 17 elements, or mineral salts etc. As long as you do not give too much, the most common mistake in this area, they plants will take what they need and leave the rest. If you apply too much then the salinity gets too high causing a myriad of problems. Too little and deficiency signs appear. But it is a relatively sizable gap between too much and too little. For beginners I would err on the conservative side until you can learn to read the plants. For instance light green or yellowing leaves means you need to feed the m a lil more. Dark green leaves or "burnt" leaf tips mean you need to lower it a bit.
I use ro water for my plants as my tap is horrendous at 700-800 ppm. The following is what I use.
Dynagro Foliage Pro
Mag Pro
Protekt
Botanicare Cal Mag Plus (due to ro water)
Liquid Karma ( the ONLY additive out of the plethora of additives I have tried that really made a beneficial difference)
Jack's Classic Acid Special (just a tad now and then to feed the pH swing)
I use the Mag Pro very sparingly in flower as high P foods are NEVER needed contrary to popular held opinion and forum/manufacturer hype
I grow in Promix HP amended with dolomite lime, diatomaceous earth and azomite cut with 40 % coarse perilite
Check these out
https://www.rollitup.org/grow-journals/358562-dyna-gro-vs-general-hydroponics.html
https://www.rollitup.org/grow-journals/429438-dyna-gro-vs-advanced-nutrients.html
Hope it helps