This is my first time trying to grow. I have looked around in the forum and have not seen a problem like this in a seedling.
I have a 2' X 4' X 5' grow box that runs a fan and 8 100w CFL lights. The box gets good ventilation and I add CO2 (Vinegar and Backing Soda) two time a day. The Temp is around 74-77 when the lights are on and 65-68 when off. The RH is low are around 40%-48% (I have started adding a bowl of water next to seedlings to help add some humidity).
I have 4 seedling that are 23 days old about 2" tall. I have been running into issues. On day 9 I started seeing some yellow in the leaves. On day 11 some brown spots. On day 14 I cut off the leaves due to the dry crunchy feel of them and figured it would hurt the seedling keeping them on. My water Ph was high and is now around 6.0-6.5. I have fed the seedlings a 20-20-20 at about 1/3 of what is directed 5 times.
Any help would be great. I have started 6 new seeds in some Rock Wool and they are looking good. Only three days about the rock wool and are already 2" tall.