Tmusic it the nail the head. You need to get some PH down and lower it. Hydro should be 5.5-6.0 somewhere in that range. I know there is natural ways if you don't want to buy the PH down, but I can't remember. I use the PH down/up

And not trying to be rude but maybe you should ditch the videos you've been watching and guides, PH is usually the first thing covered. The book phat_head menioned, the cannabis grow bible, is tops for beginers in my opinion. It's what I started with. I'm not a big grower but what I have has turned out great.