Stock Tank as Sump

[wardworld]

I'm just starting to plan my 210 build, so I'll be posting lots of newbie questions.
The first:
For those who use the stock tank type of sump (rubbermaid, etc.), do you cover it w/ something to protect against evaporation or contamination???
I wanted to use this in my fish room area, but that room may not be totally "secure" in the sense that it's a partial screened porch...ideas/thoughts???

 

[Alphabet]

You could cover it with "screen door" material. you can make a frame to fit the top. Or you can use the light diffusers, the plastic stuff they use in flourscent light applications. It is avaiable at HD in 2'x4' sections. As far as my sump, its in the basement uncovered.