Right...plain water won't work. You want a solution with maximum density so that the eggs will float to the surface and adhere to the coverslip. We use Fecasol (Sodium nitrate, I think) at work. I've heard that a super-saturated sugar solution can work at home, but I assume that if it was that good, we'd use it at work.

I have not been reading fecals on my kids, but subsequent to the Ed Clark debacle, I am in the process of collecting samples on the whole crew, as three of them came from him. I am trained to read them, and have a lab at work so I can take them in and do it myself.

Most of the bigger stuff...roundworms, hookworms, whipworms...will show on a 4x. Coccidia can sometimes be seen on 4x if there are a lot of them, or if it's a big species but just to be sure I always read on 10x, and then if I find anything I switch to 40x to confirm. Giardia are difficult to find...the method reputed to be best is zinc sulfate solution with centrifugation, which requires a swinging-arm centrifuge...most places don't have one, but we are lucky enough to have upgraded to one recently.

But yeah...for most of the worms, you can find them on a slide at home if you are experienced at reading them.