I have royal, but that doesn't seem "electric". Anyone have a tip?
Americolor sells Electric Blue.
Michael's now carries a line of products from Duff. They have food color sets, and one of them is 'electric' colors and it has blue, green, purple, and pink. The blue is exactly what you need. I used it for a cake last weekend and it's awesome. Gets very dark, so don't use too much. I think the box of 4 colors at my Michael's is like 8.00, but I used a coupon.