Little yellowing and different spots..

Hello,

I am using plagron light mix, my light is 400w hps, i am growing gorilla glue auto and using an sensi bloom a b and and cal mag extra. I fallow tang schedule. This plant is 22 days old and i saw some spots and yellowing at lower leaves. You can see on pics.

The blotches on the lower leaves say pH is off.

Hm thanks..

Anybody else??