Aquarium cover spacer (parametric OpenSCAD)

On summer the water temperature tends to rise too much, even if the heater is switched off. One solution is to open the cover to let the water evaporate. Evaporation lowers the temperature of the evaporating fluid, so the water remain within the optimal range.

I made these spacers to put the cover far enough to increase evaporation, but not so far that fishes can get out.

OpenSCAD source file is included, so that it is possible to change height and glass thickness.