baby plant dieing?

ok i have a little plant that has some yellow on the tips and one of the lower leaves just fell over today. my plants have been suffering from stretching so i put them in deeper pots since the roots weren't strong enough.

the other plant that is in this soil is doing fine and they are both the same age.

my soil:
1/2 fox farm ocean forest
1/4 fox farm light warrior
1/4 perlite

i put some cloning solution to help with the root system

grow journal:
https://www.rollitup.org/grow-journals/336092-1st-grow-come-look.html

here are the pics:

flush your soil wiht 6.8 phed water and dont use any neuts yet

k, thank you, so basically by flush you mean water alot, let some of it come out of the drainage holes? and how long till it is back to norm