Starting out: a 120-litre tank on the bookshelf
The tank is a plain 120-litre glass box on a reinforced shelf. Sponge filter, a cheap LED light on a timer (7 hours a day) and a heater set to 24°C.
The nitrogen cycle took a little over four weeks. I tested every two days and only added fish once ammonia and nitrite stayed at zero for a week.
If I started again I would buy a slightly bigger tank — stability is easier with more water.