I clean once a month also, always on the 20th. Do my spot cleaning and change his water daily even if he hasn't used it. And Lija I feel better now knowing that im not the only one that when its time to clean tanks its a whole day process. I was reading a thread and got the idea to try that wipeout1 from Griff The Great so I ordered a big jug this week. Hopefully it decreases some of the time it takes to disinfect the actual tank.