Aquarium Filter Bags
Use aquarium filter bags with loose filter media like activated carbon, which can escape your filter and make a mess or even cause damage. If you use filter bags with loose biological media - packing some into several bags - you can change out only a bag at a time, leaving most bacteria undisturbed and preventing harmful spikes in pH and ammonia.
Aquarium filter bags wear down over time; stock up on a few! Micron sizes refer to the mesh; use smaller micron sizes with fine-grain media.(If you're looking for Bio-Bags, check filter cartridges.)