Plants fast decline

have 8 plants been going good then four days ago I noticed bottom leaves rolls ng up and inward then crispy.
Now two of them look bad.
I pulled them out. But worried.
Pic 1 first plant
Pic2 second plant
I am watered last night, look so worse.

Pic 3,4,5 are the others plants
Pic6 did notice this on the leaf of healthier plants.
PS did use a foliar spray Cal mag + b1 pH 5.5 twice a week, last done 5 days ago.
Any advice, greatly appreciated.

dark green leaf with yellowing/browning leaf tip usually mean over feeding. You have to put up more info about the soil, the nutrients, how often you feed, what's the air temp, anything else. Hard to tell without knowing the details.

polishpollack said:

dark green leaf with yellowing/browning leaf tip usually mean over feeding. You have to put up more info about the soil, the nutrients, how often you feed, what's the air temp, anything else. Hard to tell without knowing the details.

Click to expand...

Soil, under 600 watt lights, temp running 75-78 26% humidity.
Soil mix is Coco coir, and super soil mixed in lightly at beginning.
Water has been running 6-6.5 pH ppm 600
Soil testing monitor showing soil oh of 7.

I think that's over fert. Are you saying that the water from your tap is 600 ppm? If that's the mixed ppm level, how often are you feeding?