Nutrient burn or something else?

I'm 5 days into flower + 2.5ml/gallon calmag. Using house n gardens in run to waste coco.
PPM never above 1000ppm. Noticing some spots on the upper foliage of 1 strain, which is purple punch from barneys.
Wondering if it's a nutrient burn or something else.

Should also mention I'm using a combination of RO and condensate as my starting water

So first the foliage is a bit greener than the pics appear, the gavita LEDs dont show great color.
Anyways, I flushed each plant with pure RO water, 2 gallons each until it was running out the bottoms. I tested the runoff and came back with 1000ppm PH 6.3.
So I am thinking they are burning not because the nutrient solution going in is too high, but because the nutrients are building up.
I figure I have a few choices
Reduce the overall nutrient strength
Increase watering frequency to 2x per day with runoff
Do a weekly or even bi weekly flush.
Thoughts?

Looks like Mg deficiency, possibly due to lockout. I'd lower the feed ppm as well.
Had the same issue, fixed with epsom salt (~1g per gallon).