First off, best not to feed your plants until they are 2 weeks old. So over fertilization is the likely culprit. But just to cover basics - you have a pH pen right? Use it every time, even if you've pHed a batch of water in advance. I suggest you flush the plants and leave them set for a week before you do anything else. Any corrective measure needs at least a week before you can tell if it's been effective. A rule of thumb is to start ferts at 1/4 strength @ 2 / 3 weeks. I go with 1/8 strength and increase from there. It's easy to add more but not so easy to take it back. Also, don't be tempted try lots of things. People always want to throw chemicals at their plants with the idea that if a little is good then more must be better, right? Wrong. So flush them and leave them alone. Finally, pictures, and strain information always helps. Oh just re-read. The MG soils are notorious for been too hot, especially for seedlings. Hope this helps.