Cracking glass canopy
I've never had this problem on any other size tank, but the glass canopy on my 20 long (30") keeps cracking in the middle. I tried the "twin-tube" version, whose glass seems thicker and which I prefer (the back section of the glass is larger, so you can leave the light strip where it is when you feed.)
I think I need something to brace the center, maybe? But it would have to be perfect or I think it'd serve as a nice fulcrum for a clean snap instead of preventing a crack...
Remember that Darwin was mostly right!