My dragon, Bulmers, just had a pinworm and coccidia issue and I was told to clean it daily during the treatment. Usually, I would do it once a week with quick wipedowns as needed otherwise. I have a spray bottle filled with water and a little bit of bleach. I believe it is somewhere between 10 and 15 parts water and 1 part bleach. I spray a few times and wipe down the entire inside and then keep hosing it down either with the outside hose or the one attached to the sink. Dump, then repeat. I do it 4 or 5 times usually. Once the tank doesn't smell the elast bit like bleach, it's ready to go. Haven't had any problems.