Originally I was rendering normal scene and bloom scene to different render targets. Then I was applied the blur to bloom texture using a UI Bitmap Element. I figured it out it wasn't working the way it should.
So, I had to make multiple render targets:
1) Normal Scene with lights rendered.
2) Bloom Scene with threshold of 0.3
3) Blurred horizontal of the bloom scene
4) Blurred verticle of the bloom scene from previous horizontal blur.
5) Output the bloomed and blurred to final render target.
6) Render 2D Quad and disable depth buffer outputting the final bloom effect with combination of normal scene and bloomed scene together.
Viola we get this:
I rendered the scene with it's original size. The bloom scene and the blurred horizontal and vertical were both rendered as 256.0f then upsized to the original size of rendering window.
I believe if I step it up from 256.0 to 512.0 then full rendering window size - there should be a very nice gradual looking bloom effect.
Next ambitious step is to work with light shafts and head back to SSAO like I was working on earlier.