To be honest, if ur a 1st time grower, I wouldn't recomend a hydro set-up, if u don't even know that u should have a ppm meter, and use sumptin besides litmus paper or a pool tester to check ur ph ur not ready for some of the difficult and very unique problems that can occur with a hydro set-up, my suggestion is to switch to soil for ur next grow cause it can be very complex to run hydro especially if u've never even grown in dirt.
Sorry I don't wanna sound like a dick and sayin ur an idiot, its just that I mean dirt acts as a buffer, in hydro there is no buffer, so whatever mistake u make u see in ur plants almost right away, but with soil grows it can protect ur plants so even when u do screw up, you can correct it without killing ur plants off.