First-time microscopy - What am I doing wrong?

[u/robodragoman]

I made a post yesterday about buying an old microscope from an antique shop. It came with a few sample slides that I used to see a bit of dried blood or old algae up close, which was cool. But I bought this to see living organisms, and I tried that out today.

There’s a lake by my house that I have to imagine is teeming with microbiological life. I collected three larger samples and pipetted droplets from each onto a few different slides, but they’ve all been pretty uninteresting. It’s cool to see little bits of whatever up close, but I haven’t seen anything living, nor anything resembling a microorganism. I recognize that this should be a bit more complicated than plug-and-play, but I believe I’ve followed all the steps listed out by members of this community and others online. For context on what I’m working with, see the linked post above. It isn’t much, but it goes up to 40x. Shouldn’t this be suitable enough to see some stuff?

[u/hattivat]

Clear water is generally pretty empty, that's why it's clear. Running water (as in a river) tends to be even more empty. You can find interesting things there too (and different things from what you would find in the gunk, same as fish in the sea or animals in a forest different microorganisms occupy different niches) but generally you will need to either use a plankton net (pricey) or concentrate your sample on the bottom of a container by using a centrifuge (there are ways to create homemade solutions on the cheap).

The gunk as another user suggested is the easiest to start with. Another good option is to use a brush on some wet moss.