Zip,
Hydrobuddy will help if you want to roll your own mix, or tweak one, or nust learn about it.
Best to start with a commercial mix if you can.
Ph buffer is important and built into some but not all commercial mix.
http://scienceinhydroponics.com/2016...program-o.html
You can enter commercial mix % into hydrobuddy, and it will give ppm. Very straighforward.