Yes Vi, and especially from a newbie perspective using Jack's Classic can be sooo simple.
I use from 1/8 to 1 1/2 teaspoon per gallon of water, depending on lighting and growth rate, indoor or outdoor etc. With indoor lighting I usually use maximum of 3/4 of a teaspoon of fert per gallon. I usually feed with each watering.
I also like Miracle Grow for Tomatoes (for Veg cycle).
Jacks is my preference though (after growing for many moons and trying many types of ferts)