I went back to find this thread (I hope you don't mind). I was wondering how this tank was doing? I'm considering dividing a 10 for two bettas or eventually dividing up a 20L like yours. How hard is it to clean?
Wow that looks great. What are your water changes like? I had been thinking about doing sand, but is there anything special you have to do when doing your cleaning?
The tank is very simple to clean, with a python, you just have to get the debris off the bottom in each section. It really doesn't take much more, if any, extra effort on your part.
Unfortunately we had a catastrophe in this tank and all 4 betta's died so it is sitting empty for now. That is the only downfall of a divided tank, but ours was a matter of too much algae killing chemical. I no longer wish to use anything like that in my tanks.