I agree that something is getting locked out but I don't agree with being over watered , because the PH in those fuckin cubes always drifts alkaline and I have to completely flush it with fresh nuts to take it back down to 5.5 then it just goes back up to 7 in a week....you are over-watered, my man. those purple stems are screaming stress. P is being locked out. back off the N, also.
LoL drowned rat ! Yea 7 Is high for cubes they are supposed to be 5.5 -5.8 6 is pushin it7 seems so benign, but i'm a soil guy. i guess in those cubes that's high. they always look as wet as a drowned rat to me