It works! :dance: Topped off and marked the level in my ATO reservoir then installed the cover at sundown last night. There was no measurable loss of water due to evaporation. The ATO level was the same this morning, and after removing the cover, I was able to wipe the very small amount of evaporation from its surface with a paper towel.
The sheet is corrugated which gives it a level of insulation. The cut outs to fit my tank were so easy, a sharp knive and scissors were all that was needed. For those running an topless tank, I highly recommend this as a night time (whenever your tank goes to sleep) assist. I also found that there was less usage of the heater during that time.
With the fall and winter months approaching, at my house the temp will drop into the low 60s at night which will create a condition for heavy evaporation from the tank at night. Since I don't have a canopy with glass cover, this makes for a great assist at reducing the evaporation.
