Egg crate light diffusing panels work well, are easy to cut, and will support a light; http
/www.collins-consulting.org/orchids/eggCrate.jpg
With a fan water will evaporate with an egg crate top, I've done this to make tank water harder before adding tap water, which is then softer than the tank water, to induce spawning. Cheaper than adding reconstituted ro, more controlled & gradual than adding chemicals to make the water harder. A good amount of evaporation will cool the tank a few degrees.
/www.collins-consulting.org/orchids/eggCrate.jpg With a fan water will evaporate with an egg crate top, I've done this to make tank water harder before adding tap water, which is then softer than the tank water, to induce spawning. Cheaper than adding reconstituted ro, more controlled & gradual than adding chemicals to make the water harder. A good amount of evaporation will cool the tank a few degrees.
