stems turn purple then die

[J DOG 6000]

PH?
And it sounds like your germinating them in too much water.ket it start to dry out a bit once the seed cracks.Like you would with soil...water let dry water...but you can't let it get too dry or the seed will die.Let dry to a damp feel not dry.
The tap roots should grow to about 3/4 s of an inch then put in rockwool and wait a couple dayz.