Personally I don't think it's a waste of money. With 32W running 8 hrs a day there's a lot more than 100mL of evaporation, plus I have a job that requires traveling on the weekends (Fri-Sun). ATO system would safe guard drastic evaporation. To be honest, I never asked what you thought of me getting an ATO but thanks for your input.
Productive criticism is welcomed.
I know you didn't ask but I thought I would share my thoughts and opinions on it. Isn't that what this forum is for? Topoffs would have to be the easiest part of maintenance. Also if you topped off on friday and came back on monday you probably wouldnt have more then an inch of evaporation.
Are you planning on using CO2 at all?
And I would remove the little clay cave thing unless you can hide it with moss or plants. It looks very un natural.