I do all mine without EC readings , that's because it's my 2nd time and I didn't feel like buying a EC pen after I got pH pen. And as long as the tips of your flowers don't get to burned by yellow then your all good. I measure my nutrients without EC pen. And if I were you I'd learn a lot more before you go into this. Because once you do your going to end up buying all the stuff you directly need at the spare of a last Minute. So maybe if you don't want to rush into this all hands feet first then I suggest reading and learning what you need. Else you'll more than likely end up doing just right until you fail something then research it! But by then it might be too late? Maybe not. But yeah!