Nalani, you have a coco starter medium and going into hydro?
Check that your nutrients are designed for HYDRO and not soil, because quality soil nutrients are designed to buffer at pH 6.7 or so, which is correct for dirt.
If your plnats are living in a coco medium for a long time, use a coco nute or add some calmag to your hydro nute.
A PPM/TDS/EC meter is definitely important for running hydro! It will make your life SO mcuh easier. I used to run without one and it was not as easy as with one- you have to change the res more often because you don't knwo your nute strength adn have to do a lot more math, lol!
I am also becoming concerned with a couple pieces of 'information' from one poster. pH is an important concept to understand if you want to play in the water!