How to make the .eps file smaller

I'm working on the large sign 24" X 60" in Illustrator CC 2014. My problem is the size of the .eps file. I'm still new to Illustrator and learning new things with every project. I'm trying to achieve the water bubbles effect on the background of my sign - image attached. I created one bubble and added gaussian blur effect and a drop shadow. I then copied and pasted this bubble multiple times all over the artboard. Now, after I saw the saved file size I started reading, I know now, that I shouldn't use drop shadow, especially when working with huge signs/banners. The question is, how can I easily replace these effects with something less heavy? Thanks!