Help, what deficiency is this? Dried up Fan leaves

[my9goesbang]

I'm on Day 48 from seed (Veg stage)
Seems like 1 by 1 my fans leaves are dying on me. 1 gallon pots I water with 16oz of water. I'm on my 3rd week of using the Happy Farm Trio ( I use half of the reccomend dosage**) On 1/16 was my 1st feeding, I normally feed it on Sundays ( I try to keep PH at 5.8-6.0) (My Runoff is around 5.5)
Feeding I use:
16oz of H20
BIG BLOOM 45ML
GROW BIG 22ML
CAL-MAG 15ML
Then on Wednesday or Thursday I'll give it:
16oz H20
CAL-MAG 15ML
.
My Temps 78-83
Humidity %40-65
SF4000 Light around %80
Light Distance 26-28 inches away
Happy Frog Soil
Top Dressed with Worm Castings (less than half a cup)

 

[GreatWhiteBud]

Maybe just senescence, older fans might just have run their course.

But it might also be Sulphur, get some gypsum to fix that.

... Or Potassium...

 

[GreatWhiteBud]

Here's a handy dandy chart I like to help find the problem.

 

[mysticepipedon]

I think it's potassium. It may be lockout from over-doing it on the cal/mag.

You know it isn't sulfur, because sulfur is an immobile nutrient and would appear at growing points/upper leaves.

 

[Madbud]

Older leaves, probably just from overwatering when they were young. New growth looks good.

 

[GNick55]

wow that’s a lot of food, especially the calmg..
how long those plants been in those pots? what size pots?

 

[my9goesbang]

wow that’s a lot of food, especially the calmg..
how long those plants been in those pots? what size pots?

1 gallon pot, next week will make a month in the pots.

 

[GNick55]

1 gallon pot, next week will make a month in the pots.

probably rootbound..