Soilless Grow - Some Leaves losing color and dying - Pls Help me out!!

These are from two plants that are currently in week 3 of flowering.

I'm growing them in a mix of coco peat, vermiculite and Perlite and feeding with General Hydroponics Flora Series 3 part nutrients. Recently was able to get some Advance Nutrients Cali-Magic as well for calmag supplements.

Feed them every 2-3 days, basically whenever the pot feels light.

Till now I have not had to check these readings because my plants looked healthy without any symptoms of deficiency. But today I noticed in two of my plants the lower leaves were starting to lose color, and some leaf tips becoming brown, drying, and pointing upwards.

Here are the readings from 24 Hours Ago:-
1 - PPM of nutrient solution going in: - 900 PPM
PPM of nutrient solution run off : - 400-450 PPM

2 - PH of Nutrient solution going in : - PH 6
PH of Nutrient solution run off : - PH 7-7.1

24 Hours Later, I just watered without nutrients and took some readings:
PPM of the water going in = 200 PPM (.4 EC)
PPM of water run off = 450-500 PPM (.45-.5 EC)

Till now I have not had to check these readings because my plants looked healthy without any symptoms of deficiency. But today I noticed in two of my plants the lower leaves were starting to lose color, and some leaf tips becoming brown, drying, and pointing upwards.

After reading through a lot of problem guides, I figured the symptoms indicate a possible Mag deficiency so I fed them 24 hours ago with an added dose of some Advance Nutrients Cali-Magic for mag supplement.

Am I on the right track??? any help will be appreciated!

Pics

Nute burn. Your PPM is far too high. Lower it to EC 1.0. But first flush with just water a few times. Your runoff PPM tells us the nutes are dense in the medium at present.

But the runoff PPM is lower than PPM of nute solution going in, I thought this means I am probably under feeding?

I just finished feeding them again, before I read your message

Here are observations from today:
Plant no.1
PPM of Nute solution going in: 850 PPM (EC 1.7)
PPM of Run off : 450 PPM (EC .9)

PH of Nute Solution going in: PH 5.7
PH of Run Off : PH 7

Plant no. 1

PPM of Nute solution going in: 850 PPM (EC 1.7)
PPM of Run off : 500 PPM (EC 1)

PH of Nute Solution going in: PH 5.7
PH of Run Off : PH 7.1

Thanks!!