1. It is not a good idea to wash your filter media with regular tap water. The tap water can kill the beneficial bacteria that is built up in the filter. Use distilled water to clean out your filter and its components.
2. It is important to pay attention to the limitations of the fish you place in the aquarium. Do not place fish into aquariums smaller than there recommended range, this can lead to increased aggression and decreased health.
3. You should keep some brushes on hand, especially if you are a reef aquarium owner. With your brushes you will be able to clean off any built up grime from inside your aquarium or on the surfaces of your hard corals.