All tips brown or dying

The tips on my babies look like they're from heat stress or nute burn. The temps are around 55-83F, PPM around 800-1000. Hydro set up with 400W HPS. It started around week 3-4 of flowering at 400PPM (water is 150 normal). It looked like nute burn, but I wasn't sure. Could of been a def? So I added more and a bunch of Epson salt.

What will happen within two weeks if the tips are being slightly killed on the leaves and tip leaves of the buds? Will it stop bud creation or make them skinny or...ah I wish I had a camera.

In hydro problem are fixed in a matter of days not weeks. Watch them closer then that. How close if the light? The temperature you are mesuring may be under the light but what is the temperature of the leaf?

If the light is to close then yes you can even burn them with that temperature range. The internal temperature of the leaf structure may be much higher then what you are reading in the air.

If you are that far into flower then I would guess it's more of a nutrient lack then nutrient burn from to much/ 800-1000 ppm is for veg cycle not flower cycle nutrients. That late into flower you should be more P & K then N at this point and your buds will be small and thinn if you don't give them the right nutrients at the proper time they need it.

That is a few things to think about.