The whole plant is yelllow, if it were nitrogen it would be starting
at the bottom, this looks like a pH problem... it is so evenly spread,
have you tested the pH of your run off?
i would just add the recommended dose of fish emulsion...its not very strong.... as you can see growing inside and in hydro is much harder than outside in soil
oh yeah and ph is like the most important part of growing indoors... gotta get a ph meter got mine off of ebay for like 15 bucks. go digital. 6.8 for soil and even lower for hydro i think like 5.8