Hey,

Listen to stinky, I assume the soil you've got is bio-bizz light mix? If it is thats the ideal soil for seedlings. It should say on the pack the ph of the soil, I use bio-bizz all mix and its got the ph on it, i think it's 6.4. Like stinky said you should check the ph of your water and your runoff as thats the most likely cause. The problem isn't with your light, get that back down close, around 3-4 inches for now i'd say.

As they're still very small I only like to water tiny amounts, probably a cup full of water will do 4-6 plants, watering every other day probably but it's best to learn when the plants want watering and not working from some set schedule.