Something wrong but I don't know what

Could any please give me some advice please,

I am currently growing 10 plants under two 600w metal halides, the are in 15 litre pots with canna coco

I am feeding ph 5.5

Canna coco a&b 10ml per 10 litre of water

Rhizotonic 20ml per 10 litre of water.

The problem is half of them are green and lush, the other half is yellow curlin inwards and don't seem to be growing and I can't see any new root growth.

When I got the clones they was very stressed, I have been flushing them for the past 3 days and raised the lights to try and relive any stress,

I have uploaded two pice of good and bad so you can see

personly i would higher the ph to 5.8 upto 6.2 i cant see any pics checked ya profile not there either bro,??

sorry about the pics, it seems they didn't upload. here are two good plants and two bad, I hope you can help!

Looking at the pictures it looks like Mg deficincy, Few of my plants just did the samething and I have been on the PC looking around. I just feed them yesterday.

Do you know how to treat the deficiency or do you just have to give them time? I have just gone back to my normal routine and am hoping it wiill rectify its self

Hopefully things are going better for you... assuming you're using good quality nutrients I wouldn't understand why you're seeing this so early on. Typically when I see problems like this, I simply flush the plant with a low strength mix of base nutrients only. By low strength I mean NO MORE than 1 ml per liter of water of A and B. If you're meausring the PPM of the mix, you should be somewhere around 350-450 ppm with the solution you use. Put enough in the plant to get run through and remove the excess from the drip pan on your planters. Curious, why do you have expanded clay pellets in the pots?

One other suggestion.. kick your Ph up to a range around 6.1 - 6.3. Being to acidic can also cause uptake problems.

Peace,

Farmer Rich

I agree, your pH is too low for a coco grow. 5.8-6.2 is good for coco. also, your P and K is too high. your N is too low.

Before adjusting nutes, adjust pH first. see if the problem corrects itself.
the purple stems and yellow leaves show signs of N deficiency, but your leaves are also showing signs of nute burn.

pH first, then nute adjustment.

are you in flower,for mag def add a table spoon of epsom salts to 5 ltr of water..i use coco AnB and i add 30 mil of each to 10 ltr bit less than they recomend on the bottle..