Plant problem Cal/Mag diff problem?

My seedlings are about a little bit over 1 week and I started noticing magnesium diff. I went to my local hydro store and got cal-mag. Just needed to know how many times should I water them with cal-mag. And how much

You should post pics I don't see Why a seedling would have any deficiency. What's your setup ? You use it every other watering at 1/4 strength..

I looked at the other threads you started and it's not a deficiency it's light bleaching raise your light. That guy that told you that knows what he's talking about. Watch who you listen to on here or youll end up with a dead plant.

The lights are we're at lest 10-12 inches high when the problem happened, the main vain was turning purple u can't see it from the picture, so should I raise the light more?