I managed to persuade one of the chaps at my LFS to lend me his microscope the other day. I wanted to see whether I could see any plankton from my reef tank. So I took a scraping from the glass and this is the result. Its abit blurred because I was trying to wedge the digi up against the microscope eye piece as well as focus it. The magnification is 45/.66 Just click on the pic.
Not bad, a lot of that will be bacteria, but you probably won't see it without staining or phase contrast. Consider that a a ml of seawater can have up to 10^6 to 10^8 bacteria, and up to around 10^10 bacteriophage. Most of which are unidentified and uncharacterised.