You probably actually want fertilizer that contains a balanced NPK mix, but higher in nitrogen, for the vegetative stage of your plants. The time-release pellet-type nutes are low-maintenance, but you'd better get the dose right, because those bastards stick around for months. Since you've already done the deed, look around on the FAQ or elsewhere for other nutrients that are high in P and K to supplement what you've already put in there. Certain types of guano are good for phosphorous (P), and others for Potassium (K). Just take a google and figure out what you can find nearby.
In general you will find that experienced growers use nutrients in liquid form for ease of administration. Exactly which brand is right depends on your medium. Usually one is used for the veg cycle that is high in nitrogen and moderate phosphorous and potassium, while a separate bloom solution with lower nitrogen, higher phosphorous and potassium content is used for flowering.