Humm ya using box blur for bloom or gaussian blur? Your blur look pretty different compared to our blur. (check the Rabbit Engine thread at Tools forum) When we use bloom in our engine the fps goes down almost by half. Our bloom is pretty simple:
Render to texture (with FBO)
Down sample 1/4 of the screen
Horizonal blur pass
Vertical blur pass
Combine

Creates pretty nice and strong bloom... Though box blur aint the best for bloom...