I suggest you read the pinned artcle on the basics of lighting. Dennerle - Special-Plant 3000K Warm, yellow/orange. I doubt it could kill your plants all together but i'm sure it's not the best you could be doing for them. Theres many factors to why they could be dying. Are you running proper substrate, are you running enough light... (again covered in pinnned article) are you running co2 (which plants need to grow), are your plants getting the nutrients they need. This is a very common thing for people to jump into the planted aquarium hobby. Trust me i went through those frustrating times, even still to this day i battle with different issues that i have to continously do research on. That's the fun thing about this hobby you never stop learning. But we are definately here to help you out. My only advice is read as much as you can, first start on every pinned article. I myself have read those things over and over and over, and will probably read them more and more lol. Theres just so much information to know about keeping a great habitat plus keeping alive everything in it. Best of luck to you that would be where i would tell you to start.