Take a look at these. I just purchased my second set of these for this years season. I have used a set for the past two years and have great results with pepper and tomato seedlings. I too just built a rack and now have two shelves for seedlings to grow on. That is why I know have two sets of lights.
I keep them within a couple inches of my plants.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1