Yellow/brown spots

I have 6 2-week old seedlings growing in my closet, they are under 300w of cfl's, in coconut fiber/perlite mix, I have fed no nutes, only dechlorinated phed water with minor amounts of trace elements in it, temps 75-80, and have a fan blowing on my babies

Recently they started showing what looked like tiny yellow spots on the leaves, which have now become dark brown. They are about the size of a pin head, and seem to be getting darker and growing
Also several leaves are curling upward on the edges in a kinda canoe shape, and most of the leaf tips are curled down and brown/dying off
I have no pictures, I can take some with my phone but the quality will be poor
Any help would be greatly appreciated

Was it Miracle Grow Perlite? Miracle Grow perlite contains nutrients (too much for seedlings). It sounds like nute burn to me.

Its shultz brand

bump....please help

did it say on the bag if it has nutes with it? also what coco did you get? was it properly washed as some of the brick stuff has loads of salt in it. either way though a good flush would be a good idea

it doesnt say anything on the bag about there being nutes in the perlite, and I looked it over thoroughly
The coconut fiber was a brick, although I thought I had done a good job cleaning it, I let it soak in dechlorinated ph'ed water for like 4 hrs then rand it through a fine screen

don't know maybe some type of deficiency if you haven't fed them try looking at this Nutrient Disorders in Marijuana Cannabis Plants