Flowering?

You should have more white pistils at this point. It's possible the darkness stressed them out so they aren't flowering yet (not sure why someone told you to do that). They seem to be responding more like autos... if that's the case your light cycle means nothing and you should be on 18/6. As for nutes, you should be between 500-700ppms at this stage. Don't switch to bloom amounts until after they stop stretching. You'll experience a week of explosive growth where they double in size. After that, they will slow down significantly and you can switch to the bloom amounts. Make sure you mix in Micro first and I recommend also using Diamond Nectar and CALiMAGic with Trio.