My favorite pet that IS guarenteed to suck up all the waste in your substrate is my python (scientific name Gravellus Vaccuumus). He only needs fed once a week and will drink roughly 25%-50% of the water in the tank. Just fill in the amount it will remove afterwards and be prepared to feed him next week.
Edit: Please take this as a joke and not any offense. Im just goofing around.
Jimmy
Edit: Please take this as a joke and not any offense. Im just goofing around.
Jimmy