$21.99 10 Pack Medium Filter Cartridges Compatible with Whisper Bio-Bag Filters, Replacement Filter Cartridge for Fauna ReptoFilter 20 Gallons (90 GPH) and Whisper Filters 10i / IQ10 / PF10 https://www.amazon.com/dp/B0DPZMF3BN?ref=t_ac_view_request_product_image&campaignId=amzn1.campaign.3UAU9PGYUKTSM&linkCode=tr1&tag=mustafakhan0f-20&linkId=amzn1.campaign.3UAU9PGYUKTSM_1754770424625