@Bombnes hope you don't mind me dropping some links and images. I'll start at the top of your list and work my way down. I only internet on mobile so please bear with me.
73 is too cold for a co2 injected room. You want above 75. 86 max 78-82 ideal. If you're running carbon scrubbers, you'll have to stay towards 75-76 because rh has to stay below 65% for them to work properly. This is VPD. We'll get into that later.
Here's my room
A secondary hygrometer in the plant canopy reads 80.
But don't take my word for it, here's a thread with MASSIVE amounts of facts and proven studies with information cited from books.
https://www.icmag.com/ic/showthread.php?t=221893
From that link "
but the commonly found ideal temp range is ~82-86'F, and that's with CO2 supplementation and very bright light." -spurr
However, taking vpd into account, rh would be way to high to run at 82-86 so 79-81 is far better .
Taking vpd into account, you DO NOT WANT A BIG TEMP AND RH drop with lights off. Its just false information passed along for decades. My room drops to 73 but I may even lesson the drop. That number will be decides by if I want a .8-1.0 kpa vpd or a carbon scrubber play it safe vpd of 1.25 kpa both night and day. Which would mean same exact temp and rh lights on and off
Source of that information
https://www.icmag.com/ic/showthread.php?t=195058
Quote "ideal VPD (i.e. 0.8-1.0 kPa) and close to ideal VPD (1-1.25 kPa) while keeping ADT (Average Daily Temp) high (ex. > 70'F) and keeping RH below ~65%, which is important for growers who use carbon scrubbers (they don't work once RH is ~65%+).
If a grower doesn't use a carbon scrubber than they should shoot for VPD of ~0.8-1 kPa for veg and ~1 kPa for flowering. But if they have a carbon scrubber than they should shoot for ~1.25 Kpa all the time." -spurr
Much better. My water never sees a second over 68 even in 24/0 1k mh veg
CO2 IS 1600 STEADY THROUGHOUT THE 12hour CYCLE
This is probably by far the worst thing you're doing to your plants.
In reference to the last link I posted with multiple studies on co2.
https://www.icmag.com/ic/showthread.php?t=221893
Anything over 1100 is detrimental. You want to stay 900-1000 with 1100 being max.
I have mine set to 900 with a 25 deadband
At night, that number needs to come down. Ideal is around 500.
If you can't bring night time co2 down , running something around 700 night and day is acceptable
"Night time CO2 should be < ~500 ppm, unless one is trying to reduce dark respiration and stretch, then upwards of 750 ppm can be used for short periods (otherwise leaf chlorosis can set in)." -spurr
Which by the look of your pictures, looks like exactly what happened.
PH is way too high. I'm using same nutes as you.
Source for why lower pH is better
As you can see on the right, micros are beat absorbed at lower pH and bottle neck at 5.8. At 5.3 you get good intake of npkmgca and all the micros too. I stay between 5.3-5.5
I run same line and 840 is too hot of a mix. Things burn around 750
GH 3 STAGE MICRO, BLOOM, GRO 1/8 STRENGTH
I use same thing. No idea what u mean by 1/8 strength. You should start with 5ml-5ml-5ml as your base
Source
https://www.icmag.com/ic/showthread.php?t=181405
Quote "By the way, GH 1:1:1 three part nutrient ratio @ 5 ml per gallon:
N - P - K - Mg - S - Ca
111 - 33 - 136 - 30 - 15 - 81
That's awfully close to Bredermann's study results (1945) in the first chart above." -Carl carlson
From here, the goal would be to get P up a smidge. Anywhere from 33-60 would be nice , then mg has to be 1:1 to p so mg would need to be raised from 30 to closely match the 33-60p. And since ca is best at 3:1 on mg, that would have to get bumped to 90-180 depending on mg and p.
Rest is golden
Snake oil, you don't need this
I'm using this as well at 5ml per gallon but that may change
Root rot in a bottle. stop using this
OGBIOWAR FOLIAR, ROOT EVERY OTHER WATER CHANGE.
If you're using RO. You should stay sterile and not use bennies. I add in pool shock solution (1 g hth pool shock per gallon ro) only once at 2ml per gallon into the system at a tank change since ro has had chlorine removed.
Waste.. I can go 2-3 weeks with just adding back nutes into epi before the stew gets out of whack
