Hi dropper,
(wrote a long reply but they only allow 1000 character) lol
In terms of recommending a good 3 part nutrient. This will depend on availability for you. Either in Europe or the U.S.
If in Europe and can get Vitalink MAX works great and easy to use.
If in the U.S; GHE (General Hydroponics) is what I'm using now. I use the FLORA 3 part range. However, I have heard AMAZING things about Blue Planet Nutrients. U.S made but because Im in the U,K I can't get them yet.
Those are just a couple of examples other reputable brands Ive used in the past are: House & Garden (The Best but expensive) and Atami.
peace. Moe