I use a hang on tank canister, which I like a lot. Going to be switching to an eheim classic soon, but whatevs.
I had my 30 as an open top tank for about 3 weeks, I couldn't keep on top of the evaporation, and I found a neon tetra on the carpet just this morning, so it has a glass hood on it again. I left the back plastic strip off though, however even without it it tremendously helps limit evaporation.
Ran it with the hood for about a month and a half, about 3 weeks without it, and now it's back on. I definitely noticed a difference, even without the plastic strip on the back.