There are literally TONS of post on fertilization - some confusing, some more common sense. Ferts are in two groups: NPK (primary basic fertilizers) and traces and people commonly dose them on alternate days. For pre-made fertilizers, Seachem, Kent, and ADA are good commercial brands. Start with dosing instructions on the bottles and see how your plants react. After a while, you will figure out that pre-mixed fertilizers do get expensive. That's one of the reasons people buy specific chemicals and mix their own.
Read some of the posts, give it a try with commercial pre-mixes and ask questions: we are here to help out.
Courtesy * Integrity * Perseverance * Indominable Spirit * and Self Control
Tenets of TKD