Yellowing issue flowering stage

Hi, got roughly 4 weeks left of flowering and one of my plants has turned almost all yellow/light green. At first i thought it could be light burn (might still be it?) but i doubt it. The top leaves are a yellow/light green and the lowerdown toward the middle are yellow and lower down again are yellow. This is in a double system and the other plant in this system is nice and green with no yellow leaves really but is under a parabolic whereas this one is under a euroreflector. I have another 2 under euro reflectors and are slightly yellow also but no where near as bad as this one, the plan looks fine and is still budding and doesnt look like its dying, the roots look the same as the others aswell. All my other plants are nice and green with a few yellow leaves here and there but nothing like this. They are all fed on the same nutes. Any idea what this is?

edit: forgot to add, there is plenty of oxygen going to the roots, a 3600ltr/hr pump with 5 air stones in each side of the bubbler for each plant. Running these under 600w hps, using canna aqua nutes. Hydroponic bubblebox system (double system)

What and how much are you feeding?

I've had kick ass weed that was kind a yellow before sometimes it is just a strain thing too

To much P

Im feeding Canna Aqua Flores A+B 250ml of each and 100ml of Regen-A-Root. Mixed into a 100L water butt. Im using the same mix of nutes for the rest of my bubblers and they are all fine, seems that only the ones with the cheap euroreflector shades are the ones that are having this tint. The recommended mixing instructions is 30ml to ever 10ml for the a+b so that works out as 300ml of each per 100l but ive always stuck too 250ml and never had issues. Regen a root is 10ml per 10l so 100ml of regen a root. How can i be giving my plants too much P if im sticking below the recommended mixture. If its related to the ones with the 3 euroshade reflectors it must be bleaching?

Not bleaching.

Someone can correct me, but bleaching will be limited generally to upper leaves and will be more of an off-white than a yellow. I've had young plants grow right into a T5 and the bleaching was obvious.

michaeljones2013 said:

Im feeding Canna Aqua Flores A+B 250ml of each and 100ml of Regen-A-Root. Mixed into a 100L water butt. Im using the same mix of nutes for the rest of my bubblers and they are all fine, seems that only the ones with the cheap euroreflector shades are the ones that are having this tint.

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The correlation to the reflectors could be that they're receiving more light and feeding more.

It looks like N def to me. So many ml of this and that doesn't say much about what you're actually feeding. The resulting NPK ratio and ppm would be more informative.

I created a spreadsheet which makes it relatively easy to figure this out.[1]

1. Plug in all the NPK values of your products into the 1-20 tabs.
2. Plug in the actual amounts you use into the "Unmix" tab. It tells you the ratio of "parts" used of each (by weight).
3. Transfer those parts (and total weight) into the "Mix" tab which will tell you the NPK ratio and PPM. From here you can vary the parts to get a better NPK ratio and PPM, and it tells you the actual amounts to use.

This would give you an idea if it's too little N, too much P.

[1] Your products NPK values must be a percentage of weight. I.e., the US way these numbers are published on labels, not the Euro way which I believe is percentage of volume. If your labels are the latter, you'd need to work out the percentages of weight. I'm sure there's some tool to do that because it must be a common requirement. But, I'm not familiar with it.

thanks for the replies, i will work out what i am feeding and what amount this evening i'll be using that spreadsheet cheers. Ive uploaded a few more photos to with the lights fully off this time.