Anyone have any suggestions for keeping water in a shallow aquarium/paludarium clean? By shallow, I'm thinking 4-6 inches of water for Spotted Turtles. I am assuming that being turtles, they're pretty messy, and would need a really strong filter. But the strongest filters seem to move a lot of water and are more suited to deeper aquariums? PLEASE NOTE I am in the research phase of turtle keeping and I do NOT currently have any water turtles.