Leaf yellowing and necrosis in undercurrent

Hi

I have a uc6xl in a 9x5 tent and I transplanted them from an ezcloner yesterday and I’m having some issues with some of them as you can see in the pic.

I have the following environment:
Ph:6 (yellow)
Ppm: source water was 21 now 26 and it’s lower then 100-200 because of tea to prevent root slime.
Tea: Heisenberg’s https://forum.grasscity.com/threads/heisenberg-tea-summary-cheap-easy-beneficial-bacteria-to-cure-root-issues.958893/
Temp:72-75•f
Water Temp: 78•F is ok according to tea directions and hopefully will promote root growth. I was planning on turning it down as the roots fall past the basket of hydrocarbon
Humidity:70%-75%
light: 2x 600 watts dialed back to get 100 - 110 micro moles
Fan: True, it’s on low
Water level is up high all the way to the top of the net part of the basket. Air stones at the bottom. The pump came with the system.

I can’t really think of anything else. Please note I have to use tea or I get root slime even with sterilizers.

What am I doing wrong?

They are getting much worse rapidly. Here is a new latest pic. The others look a little droopy now but the roots look white. I’m gonna turn down the water temp to 68 and empty the water so I get 0 ppm water then add nutes. This is what I did last time.