Great Plants Gone Bad ?? Help

Never started a thread so go easy on me here, I have three plants in my Flowering room 3rd week and they are looking bad.
they did great for a week and i went to go full strength on my nutrients and boom they went to hell.
I backed back off on the nutrients to 1/2 and checked the PH which was at 7.8 and lowered it to 6.5- 6.8 .
I flood three times a day i'm on 400 watt hps 12/12 hours and my plants are a day into this new set-up i'm going to keep photos everyday to keep everybody up but if somebody has any ideas please help me out here.
Nutrients are dyna-gro Bloom 3-12-6
Last picture is mother plant and it does really well. I'm hoping they just went through alot in a couple days and they'll bounce back.

Id say the ph was way to nigh.Go straight watre for 2-4 days flush the plants then come back with 1/2 strength nutes and keep an eye if all goes good increase to 3 quarters til finish.Is the heat an issue Keep room 78-80 max and make sure a fan is blowing to get stale air moving so plants dont sufficaite.Air is very important.

Yeah I hadnt thought of that (going to straight water for a couple days ) but it makes sense. I'm gonna get it going in the morning.
Thanks alot I appreciate it . by the way is my ph adjustment good ? 6.5-6.8 it's usually 7.3 or something. but i'v ebeen lowering it.

No problem post back and let us know if that helps