I have a small 3 gallon glass tank that is simply overrun with copepods and cyclops. I try to treat them nice and even put them back in the tank after their stint on the slide.
My well slides are made from a flat slide which I glued a "window frame" affair made from thick acrylic salvaged from bubble wrap they sell the more expensive items in. The glue is clear nail polish. You can't tear this stuff, almost can't cut it. It must be a 16th of an inch thick, but works very good. The bugs have room to move.
A friend of mine has sent me some round glass IR filters that I put over the outlet of my field lens, under the condenser, and it seems to virtually stop 90% of the heat coming off the halogen lamp housing. These are amazing. I'll try to find out where he bought them.
Here is a link to the place that sells them;
http://www.surplusshed.com/
Then search for heat absorb.