Sand sifters are animals that move the sand bed, and the latter eat remaining food matter that fell down to the substrate, keeping in mind an animal can be both. Since I'm intending to add some substrate for my turtle, I need a way that keeps it clean without forcing me to clean it manually, which, of course, is quite a chore. I need sand sifters that cannot damage my turtle(even unintentionally), and also that my turtle won't eat. I need them to be efficient and effective, as well as low maintenance.
What are some good inexpensive and independent sand sifters that can help clean my substrate?
Even if they were relatively expensive and/or inappropriate for this cause, a list of different sifters with some info will definitely be a plus to the answer.