Young clones dying need help pls

After using plain water flush system for a day. I think Im good go.
but 12 of them only three survive, Im thinking if I should put new clone in the system right now or wait a week or so to do that.

Im sure res dont have CI left, do I change out the water again when I adding nutes?

appreciate for all your feedback here
cheers

add it to your res, if its plain water no need to waste water in re filling.