Severe discoloration and brown spots, week 3

Dwc 3 weeks in. Ph is around 6.1 and ppm is 750

The discoloration have been there for a while. I suspected it was first because i hadnt cleaned my reservoir properly after last grow. So i cleaned it and put it back in. Brown spots kept appearing after res clean and change.

The white i suspect my be my new LED light, i got x2 260w leds, its about a meter above the plant and one of them is off, other i ran at 80% power.

I am using GHE grow, bloom and microflora with hydroguard

Please help!

Looks like to much nitrogen. Or magnesium deficiency. Are the roots super white or yellowish/brownish?

A bit brow ish maybe? I do have a bottle of cal-mag but read that the GHE should have enough.

I thought the roots was a bit discolored, but not slimy or anything like that.

I will add some pictures of the roots later

I changed the res, there was a lot of brown sludge in there. Looked like GHE micro. I scrubbed the tank with some soap and cleaned it off. I also had a light leak into the tank, which i fixed

After setting the system active again i have same foam in the res and I dont really know what the next step should be. Its the first time using this nutrient.