Anyone know what this could be?

[kentboy1296]

The whole plant looks to be turning yellow
Day 20 flower

Temp is always 70° - 80°f
Rh is 20% - 30% the ph fluctuates from 5.7 to 6.4 (i adjust daily)
Ppm is 640 (aprox 220 ppm calimagic) right now using gh floranova series with armor si and calimagic, been using ro and tap water (tap comes out at 130ppm) the light im using is 630watt cmh with 120true watt blurpy. Im using the gogrow 4 pot system (autopot knockoff) straight coco with hydroton at the bottom

 

[Old Salt]

Excess phosphorus causes interveinal yellowing of newer leaves, and plant shows symptoms of calcium deficiency
Spots on the leaves indicate a calcium deficiency
Are they turning yellow from the bottom up? Nitrogen deficiency

There's more possibilities. A side view of the plant would help.

If you are running RDWC, consider a larger reservoir. If it's DWC, consider larger buckets. More nutrient solution will help limit the pH swings.

 

[kentboy1296]

I suspected calcium, It looks to be starting from the bottom up. I usually run the gh trio but tried gh floranova this time

 

[Old Salt]

Nitrogen deficiency is what I'm thinking. Take a look at Jorge Cervantes' chart 'Cannabis Nutrient Deficiencies & Excesses.' It's freely available with a google search.

1. Lower leaves turn to yellow
2. Leaves lose luster
3. Yellowing move upwards
4. Leaves continue to yellow, curl, and discolor
5. Leaves start to drop ...

I'm seeing the yellowing starting from the bottom, and moving up. The fallen leaves seem to be a bit curled, and discolored. During the stretch and early in bloom, the plant needs nitrogen for the fast growth it's going through. I'd go back to at least the formulation for transition for a few days.

 

[kentboy1296]

Ok, thanks you so much for the help