is glass that good of a insulator?+1 on glass lids. Cheap and effective. Remember evaporation is a cooling process. The glass will minimize evap. And help insulate.
Put a canopy on later for aesthetics.
Compared to what? There are better but for the purposes here no its probably the best choice. Like I said and Swoll929 said part of the issue is cooling from evaporation glass top will help eliminate that part of the equation and keep the water where it needs to be. My fish tank stays at 76-78 year round my house is typically at 68-73 depending what time of year, has glass lids and the air between the glass and water is noticeably warmer then the air in the room. Glass is a better insulator then air, Acrylic is better then glass, if you didn't need to see in the tank foam insulation would be a good choice.....lol. For your purposes glass would be the cheapest and easiest way to help. You can get sheets of acrylic and make tops remember though its not as ridged as glass so it will bend and warp allowing air in/out leading to cooler or hotter air at water surface and evaporative cooling.is glass that good of a insulator?
I mean doesn't heat pass through glass really fast?
Where did you get your lids?I think you'll be alright with just a glass lid. In my opinion canopies are extremely expensive for what they are. Some that I've seen are more expensive than the stand. For a 180 gal 6x2 tank the glass lids are ~$70. The canopy that matched my stand was priced at $330. I quickly looked up the price of glass lids and said no to the canopy.