ARRRGGGGGGHHHH.......whats wrong with my plants.

hello folks help needed !!!

these plants have been really doing my head in at the min.

currently in veg growing in coco. using HESI coco nutes & following the schedule but giving half doses at first then up to full dose.

the leafs are turning crispy starting from the tips / edges working there way up the leafs & dying. the plants are also turning very pale & seem to be showing slow growth.tested the ph levels & the run-off they are ok.

1) ph level at 5.6/5.8
2) whole plant turning pale
3) leaf tips tuning brown / crispy starting from leaf tips / edges
4) slow growth

im hoping its something like needing phrosphorus,which im looking into at the min.

i really need help on this one please people ....

Post your lighting and it's distance away from the plants. Post your airflow setup. Post the temps where the damage is worst.

Phosphorus could be an issue but if it is, it's not the only one.

How are you measuring pH?

measuring ph by digital ph meter. sorry forgot to mention ph was 7 to 7.2 last week before i got a tester. lights are 2x 600w around 1 1/2 to 2 ft above 16 plants.tent size 200h x 240l x 120d. small fan for clean air (intake). large oscillating fan inside tent. 1 X rhino filter & extractor fan. temps are 21 to 23 degrees.

the HESI nutes are supposed to contain all that is needed from start to finish & from previous ecperiance have been ok.
however with the ph being out before last week,im wondering if the plant has been unable to get enough from the nutes as it should be about 5.6 for coco.

how far is your lighting an wuts the ventalation setup?

lights are about 20 inches plus from plants.the ventalation setup is more than plenty. the extracted air nearly blows my hair off coming out of the ducting.!

how long since watering?

man those fuckers have all sorts of issues. I still think nute burn and some lock out which always make me think about PH. Have you properly calibrated your ph meter? What is the ph of flush water coming out of the container?

Foliar feed with a DILUTE balanced grow nutrient for now till you figure out what's going on down below. that would be my recommendation.

I think you've got most of your problems on the way to being fixed. What's going to happen is the new growth will be nice and green while the plants still have all those damaged leaves that won't heal themselves. Once you're sure the new growth is ok, start cutting off the worst leaves a little at a time. Your coco fertilizer is just a hair on the low side for Phosphorus so it might be a good idea to find a second fert to suppliment it. Guanos or Bone Meal can be found with high levels of P. It's always a good idea to have at least two fertilizers as no one fert supplies everything that every different strain needs.

going to get some phosphorous today & see what that does. looking at VINTAGE BAT GUANO. is this ok for coco do you know & how much to feed them ??

last week when i managed to start PH testing my run off was 6.6 / 6.8 now its down to 5.6 / 5.8 so i suppose that ive probably had a nute lock-out or something causing my plants not to be able to get all the nutes. my tap water was around 7.2 PH so probably just decreasing that should help them.
meter was pre-calibrated when it come but i re-calibrated using the solution with the tester.

thanks to those who have helped. i will keep an eye on them & see what happens.

update on the situation.......

problems still the same,flushed with ph corrected water still the same.

i eventually took some pics & went to the local hydro store, shown pics to the dude he said.... its humidity the plants are getting poor air quality thus drying the leaves & dying.
so i got a mumidity meter,went home and soon as i put the meter in it went straight to 20 % humidity.

so humidity obviously the problem now how to raise it ?????

ive tried lots of water in buckets / emptied on the floor & purchased a humidifier but it will not pass 30% humidity????

any ideas anybody to raise the humidity higher ?

if you fans are blowing of your hair off, you could always use a fan controller and slow them down a touch, less air flow will help raise humidity.
This should be fine as long as your room air is still being cycled enough times per min. And you already have low temps so an extra degree or two should be fine for them too.