leaf curling some nute burn lots of pics need help

[Poke Smot]

my plant is around 5 months and 2 months into budding very slow grower i have them in DWC bubble system and a 400w hps air cooled fan always running temps around 75-80 degrees nutes at 1650ppm fell from 1800ppm the ph is right on 5.8-5.7 and is still inch higher on one branch keeps growing up. i have leaves curling at the side tips upwards look at the pic and please help me

 

[Poke Smot]

 

[Ms.Fox]

How far away are the lights away from your plants?

 

[Poke Smot]

1 foot with air always blowing on highon the plant and light

 

[Ms.Fox]

What do your roots look like? Any ph fluctuations?

 

[Poke Smot]

roots look good little dark black just a little near the net pot yesterday i added some peroxcide with a siringe spraying the roots with around 20 ml as for the ph it likes to go up slowly fast near the third week of the bucket not being cleaned.

 

[Poke Smot]

i also have some leaves dying about 5 -10 a day need some help anyone out there.

 

[lavendar]

ok,
was looking at your pics, and they were twins of a couple of my plants...what i did was look at soil first, since now that is what i'm using....it had miracle gro in it....so i repotted, wizard soil, watered plain for a wk+...kept on the dry side..also i checked the roots, a little damaged but servicable...then after ten days, i started using a liquid fert,for the aeroponics i would like to try soon...seems to have worked as it is in bud and healthy now....i am thinking about going to one complete system for ferts, veg,to bud and clone....any referrals out there that work, or any idea what it actually was...or what i did that solved the problem...
i have kept a complete journal with pics....thank you...granny doc

 

[Poke Smot]

Ms.fox,IRIE help help help please

 

[Be Irie]

It just looks like you are burning them to me.. I am not a hydro guy but can you flush them and then drop the PPM a bit to see what happens.

 

[CharlieMopps]

^^What he said. I thin the nutes are a bit strong. See if you can get that temp down, like 5 degrees even. And 1 foot away for a 400 watt sounds a little too close to me.

 

[Poke Smot]

ok iwill get the temo down a little and i will fluch todayi think i will go to soil next grow thanks guys