Should I add any nutrients at this stage?

A seedling can power itself for 10-14 days, but it's also safe to have an normal level of nutes in there relative to hydro... shouldn't be more than 600-700ppm for the most part, maybe a bit higher if properly supplementing CO2 and tight control over climate. That level of nutrients won't damage a seedling... it's far lower EC than what you see in potting soil, for example. If you want to be careful, start half strength the first week or so. If the plant shows any sign of paling at this stage, you know it needs more. changes in diet are immediate with hydro, so just keep an eye on it and it'll be fine. i'm in soilless. I gave initial irrigation at ~500ppm (calculated from labels and excluding tap water contribution). That's about 75% of normal for me. YMMV, as that sort of stuff is impacted by local variables. i've also given full strength from the get-go with zero problems. These words are a bit dangerous, because some people treat the plant like foie gras..