Magnesium deficiency?

Hey guys!
it seems that my plants are only getting worse.
When you increase the pH to 6.3 the next day it drops to 6.0 / 6.1
I'm using GH basic feed charge with CALiMAGic, drip hydro system, clay balls,
Humidity and temperature are ok, gnats made a brief attack but only it.
Why is ph falling? Normal?

photos

I see you're using LED's. How close are your lights? They'll fry your plants. I think you want them much farther away than HPS.

If they are not too close then that looks like nutrient burn. Flush with plain water and hope for the best. After a week reintroduce nutrients at 1/4 strength and work your way up 1/2 strength.

You may want to take pics with your light off but does look like xtsho says.

Whats the canopy temp?

PH is fine.

Just for reference regarding distances from LED's

Type of LED Grow Light Distance From Plant
1W Bulbs at least 12" (30cm)
3W or 5W Bulbs at least 18" (45cm)
High Wattage (300W+) up to 30" (76cm) or more

If you got that covered then you definitely have over fertilized and nutrient burned your plants. I agree with Lucky Luke. Turn the lights off for a minute and get some decent pics. Can't really tell exactly what's going on with all that purple.

Thank you xtsho!