does the hyponex have any nutes in it?

also, the pH is on the high side. 6.3 is ideal.

are you getting adequate drainage? are you sure that's 35% perlite/vermiculite? it might just be the pics.

the cotyledon, the round leaves you refer to yellowing basically are food storage for your seedling.

someone else will be in here shortly i'm sure.


-shake