Compatibility Compatible with 135 fl oz / 4 L wireless cat water fountain Regular filter replacement the filter and sponge every 2 to 4 weeks more often if you have multiple pets Triple Filtration System Three layer filtration for cleaner water density cotton filters hairs and debris to keep water clean Activated carbon removes chlorine and odors to purify and refresh water Ion exchange resin filters heavy metals and improves taste Filter Sponge and Pump Sponge density prefilter sponge further filters out impurities to maximize filtration density pump sponge traps impurities to prevent them from entering the pump, helping extend pump life Benefits at a glance Keeps fountain water clean, fresh and better tasting for your cat Reduces odors and improves palatability, encouraging better hydration Protects the pump by minimizing debris ingress and extending service life Simple maintenance with clearly referenced replacement intervals Practical use scenarios Single cat or small household: maintain clean, appealing water for daily drinking with minimal maintenance Multipet household: robust filtration that handles higher debris and hair load, keeping water fresher longer Sensitive or picky cats: improved taste and odor control can encourage greater water intake and hydration Notes Regular replacement intervals are recommended to maintain filtration efficiency and performance The system incorporates a three stage filtration approach plus dedicated sponge filtration to optimize water quality and pump longevity