germination/young seedling help

Hi, You're growing on an inert substrate. That means they might need a more constant feeding because the substrate will neither hold the nutrients nor have that buffer effect that soil has. If you gonna feed more times watering less each time is the way to go. Yellow on the new growth would indicate need for Nitrogen. However other nutrient imbalances might indirectly affect the uptake of Nitrogen. Best way to answer would be knowing what nutrients you're using. Even so I would risk saying you should adjust for more waterings like once a day and increase when its drying faster. Give it a regular feeding of CalMag supplement and raise the Nitrogen feeding a bit more. Take care some CalMag products already contain plenty of Nitrogen so in that case just by feeding the Calmag you're already increasing the Nitrogen feed. I'm sending you a link with some diagnosis and pictures. growdiaries.com/journal/cannabis-nutrient-deficiencies-guide