check your drainage. Give 1 tsp calimagic/gallon of water, make sure u are PH'ing to 5.5-5.7.
Keep an eye on your NPK numbers and cut back on the micronutrients.
Also, check how cold she gets at night.
I am looking better. New growth all looks great and the death stopped spreading. I really worked on dialing in my temp/humidity conditions by adding a small thermostat programmable heater and a tiny little wand humidifier thingy.
Figuring my problem on the white widow was both a calcium and nitrogen deficiency. The critical widow looked like cold, nitrogen deficiency and maybe a Phosphorus deficiency.
At first I thought it was too many nutes cause they were so little. But there was no way. I gave them nutes 1 time and it was 1/6th of the seedling stage and at this point they were on there third node when they got such a little feeding. The grew up overnight after the first nutes. Then they started to look sick (cold), then I immediately flushed thinking too many nutes. Then they just got deficient. I think.
I really don't know, but thats what I have been treating and it has improved.