DO clean my bowl once a week if it has no filtration. Keep around a 2 1/2 gallon plastic water jug to pretreat water for my weekly cleaning: fill it with tapwater, add 10 drops of Amquel (to remove chlorine, which kills me) and 10 drops of Novaqua, one teaspoon of aquarium salt (not table salt!!). Make sure water is the same temperature as my jars water.