yellowing leafs, 4 weeks in flowering

HYDROPONICS/Aero Ponics/Coco/Soiless/

How long has this problem been going on? some days
Are you growing in a PVC grow tent? (example: Hydrohut or any other non brand tents) no
What system are you running? (DWC? Ebb flow? Aero? Water Farm? Flood Tables? and so on...) handwatering coco
What STRAIN are you growing? durban poison
What was the establishing technique? (Were the seed or clone?) clone
What is the age of your plants? 4 weeks into flowering
How long have they been in there mixture they are in now?(coco,soiless etc..) all the time
How tall are the plants? 1 meter
What PHASE are the plants in? (seedling, vegetative or flower) are the plants in? flower
What Technique are you using? sog
What substrate/medium are you using?(Hydroton, RockWool etc.) coco
What is the Water temperature?
What color are your roots? White? Brown? Are your roots slimy?
What Nutrient's are you using?(If growing soiless) canna coco
How much of each nutrient are you using with how much water? *Knowing the brand is very helpful* canna coco 15ml/11 liters of water, bloom booster 15 ml, antazyne 22 ml, extra kalcium around 0.5 of ec
How often are you feeding? (If using soiless) every day
How often are you giving nutrients? (If using soiless) every day
If flowering, when did you switch over to using Bloom nutrients? 2 weeks after bloom
What order are you mixing your nutrients? (example: veg nutes 1st, bloom 2nd ect)
What is the TDS/EC/PPM you are using? 0.85 EC
What is the pH of the "Tank"? 5.8 runoff water
Are you sure your calibration is correct on your equiptment? yes
When was your last watering?
What is your water temps?
When was your last feeding change? (ie. grow-bloom-micro-additional)
How often do you clean your system: example: Flush out water replace with clean water and nutrients?
What size bulb are you using? 2 x 600w hps
What is the distance to the canopy? 50 cm
What is your RH Factor(Relative Humidity)? 40%
What is the canopy temperature? 29 c
What is the Day/Night Temp? (Include flucutaion range)
What is the current Air Flow? (cfm etc.)
Tell us about your ventilation, intake exhaust and when its running and not running ?
Is the fan blowing directly at plants? yes
Is your water HARD or SOFT?
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?
Are you using water from a water softener?
Has plant been recently pruned, cloned off of or pinched
Have any pest chemicals been used? If so, What and When?
Are plant's infected with pest's


What u think this is? started getting this after 4 weeks in flowering. thinking potasium or magnesium.

I think I also Have the same problem

mostly coco/perlite
biobizz nutes
hand watered
43 days into flower
40% humidity
HPS light
Snowdog BX1

Regginata, the burned leaf tips would lead me to believe you are actually over-ferting, although it's hard to say for sure without being able to see the color of the leaf.

please, I need some help. got some new pics

Overview









The problem

MrT, did the problem appear on the lower leaves or the upper leaves first? If it's only in the upper leaves, that's a sign it's a nonmobile element - if it's in the lower leaves, that's a sign it's a mobile element. I can't really look into it further right now, but I'll take a closer peak later.

its in the upper parts, but not the fanleaves. Im doin it sog style, so I cut off all the lover branches and leaves 2 weeks in bloom.

like you see here:

http://www.icmag.com/gallery/data/500/21006P1010005.JPG

im a few weeks further along than u but my leafs are yellowing just like urs and its supposed to do that when u place the plant into flower it goes into its reproductive stage then the final stage of dying so leafs yellowing esspecially the big fan leaves the deff its going through there is also known as nitrogen deff and if u want to be a complete retard you could feed em some notrogen but N and flowering dont mix if u notice all your flower nutes there N-P-K ratios for flower are 0 i noticed these are old posts but for future reference ive been around this almost all my life and ive yet to see a plant come out of flower without yellow dying or dead leafs really i wouldnt worry about it check ur ph n ur ppm if u do that for coco i dunno never used it never seen anyone using it either so