Leaves Drooping, Turning Yellow And Purple. Any Ideas?

[8zlag]

So I have 6 315 w CMH lights, I'm currently at day 45 of flower (last grow they went for 12 weeks). I've been feeding then with Canna coco A+B at a rate of 35ml per 10L
I've been feeding power si, and Cal mag in addition at the recommended doses. I added pk boost in the 4th week as well at 3ml per gallon. The pH is adjusted to 5.8. I'm growing in a coco perlite medium with fabric pots. From week 3 till two days ago I was running CO2 at 1500 ppm. Two days ago I cut it off. Temperatures have been at 82 F with humidity fluctuating between 45-55% during the day. At night the temps go down to 76 and humidity remains at 45%-50%.

I was initially running 4 lights up until week 3 as well. Then I got some extra funds and said why not add two more lights. Been trying to figure out if it's deficiencies, light stress, or heat stress.

Also there are some that are majorly leaning and they aren't experiencing the discoloration. Any help is appreciated, thank you.

 

[Aedifex]

Adding lights has a compound effect on your plants. More light = more photosynthesis = more water uptake = more nutrient uptake = CO2 uptake = more waste build up in your growing medium. Also, adding 50% more light halfway through flower... good way to overstress your plants. Regardless...

Your leaves are droopy. Indicates you have a root zone issue. Could be the plants are just adjusting to the increased transpiration caused by the substantial increasing in light. Are you watering more and more often?

I’m assuming you’ve increase the amount of runoff since increasing the light? Have you flushed? Increased uptake coupled with increased waste production can cause lockout from salt/waste buildups.

If I may though... why 1500 ppm CO2 with 1200cmh in what looks like an 8x8? That’s a good amount of light for your typical ambient CO2 levels. Bump that up to 2400W though... that’s where you’ll get the added benefit. I run 600W/4x4 without added CO2.

It’s a balanced equation with everything being directly proportional to CO2 levels: more CO2 means you need more light for the plant to uptake it but also means more watering, flushing, higher nutrient strength, etc... or it’s just a waste.

 

[8zlag]

Yes I've flushed
no it wasn't 50% mid flower it was early flower week 3 out of a 12 week flower... Still stressful but not too bad.
Regarding the co2 I was advised to keep it at 1500ppm given I'm using a tank in an unrelated garage and it's costly to replace.
I fixed my ph and things checked out, and I added a little more Cal mag.
Thanks for the response.

 

[DieselDuds]

What's your nutrient ppm' s what's your runoff ppm's looks like to me that it's toxicity and needs a flush and a week to recover

 

[DieselDuds]

Also check your pot temperatures. It's winter and floors get cold

 

[8zlag]

Also check your pot temperatures. It's winter and floors get cold

It was my reservoirs temps that we're getting cold. Bought a heater for my water small thing goes inside the reservoir. Thank you