Oase Replacement Filter Cartridge for the BioStyle

This set includes four replacement filter cartridges for BioStyle 20, 30, 50, and Thermo 30 & 50 filters, providing 5 stages of filtration.

• The description claims that each cartridge should be replaced after 4-6 weeks.
• The description claims that changing the filter cartridge improves water quality by removing debris, waste, odors, impurities, and harmful nutrients.