Problem - Help

Hello Gromies , I was wondering if you could help me. I have 2 cherry pie plants,( rockwool 6") both in veg. But one is not happy. I decided to check my TDS / PPM run off to see if I have salt build up. Turns out I did have salt build up. I was feeding 1100 ppm and 5.8 and the run off was 1700 ppm and pH at 6.0. I followed with a flush and then added fresh nutrients at 1000ppm and 5.8 ph. Made sure my run off was the same as my feed. I did this for both plants ... One is happy and the other got worse.
I don't know if sick plant might have root rot... Because I checked under the rock wool and one or two roots had a bit of black on it. The first 3 photos are before the flush and the 4th is after the flush. Please help ...
My room temp is high of 28c and low of 26c
Humidity is high of 60% and low of 40%
Water temp when I fed them was 26c

Sugar Tree said:

Made sure my run off was the same as my feed

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seems to me that would tell me they aren't eating.
2EC is your problem I think.

But why after a flush and then a burn on one but not the other sister ....

rkymtnman said:

seems to me that would tell me they aren't eating.
2EC is your problem I think.

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Like I can bring it down to 800 ppm's and see how that goes ..

Sugar Tree said:

Like I can bring it down to 800 ppm's and see how that goes ..

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600 ppms should be all you need IMO. going in should be greater than going out

rkymtnman said:

600 ppms should be all you need IMO. going in should be greater than going out

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You got a point there... I'm not listening to my plants ...

Agreed on the 600 range. Keep nutrient ppm low until plants ask for more. Easier to give more than remove too much.