Water turtles, like the alligator snapping turtles, generate much more waste than fish, and it is a good practice to invest in the most powerful
filter one can afford. The best type is a combination of canister type external filter with an internal sumersible filter. The last one
will take care of the main particles in the water, and can be easily cleaned often. The large external filter will take care of the
main mainenance of the waters condition, and left alone for longer periods of time it will provide both mechanical and biological filtration.
The general rule for buying a filter for aquatic turtles is one - the bigger the better !