Clones growing new yellow leaves, first time grower need help! (Pics included)

i am a first grower, growing in DWC bubble buckets. growing 3 pure kush and 2 bubble gums.
i got these clones in 1.5 inch rockwools 4 days ago all were showing some roots so i put them into my 6" rockwools in my dwc water. first day they started turning a little yellow but after adjusting ph they went back to green, now today the 3 pure kush strains (other 2 bble gums dont seem to have any issue) have small new grown leafs coming from top that all look pale/ yellow. what is going on? . (if you think its nute burn please tell me what i can do)
Ph is @ 5.5-6
water temp 69-72
room temp day (78-80) night (72-75)
nutes i am using is botanicare, pure blend and cal mag.
I am using tap water until i receive my r/o system next week. i get 400ppm

total ppm after transfered into 6" rockwool is 1000 (tap water ppm included) 5ml pure blend / gallon and 2ml cal mag /gallon.

should i be worried about this at all?

any help is appreciated!
i also changed water today and reduce ppm to 750-850

how much nitrogen does your fertilizer have?

Maybe theyre too wet,if they were freshly rooted clones and you put them into a 6" rockwool block and then into a drip system it might be that the rockwool block is too soggy and inhibiting new root growth