Citadel Blue Horror Layer Paint is designed to be multi-layered. This light blue color is slightly transparent, so you can use it to build your color over several layers until you're happy with it. Now the paint does require a bit of practice to use, but the results are well worth it.
The layer paints are best used as a 2-step highlight, so two paints for each color but this is a guideline. For example, Blue Horror can be combined with Fenrisian Grey. You start with the darker of the two and apply it to the surfaces that you want to eventually provide this light blue color.
Because the paint is a bit transparent you will continue to see the base color a bit, but by using Blue Horror together with Fenrisian Gray you can use that transparency to apply the layers. If you apply the lightest color after the darkest color in maybe 1 or two layers, the last highlight of the lightest color will ensure that you have a great result.
The color of Citadel Blue Horror (22-84) is similar to: The Army Painter Gorgon Hide (WP1428).