OAK Refills & Filters | The Liquid Tree

Keep Your OAK Living at Its BestYour OAK — The Liquid Tree works hardest when its algae is fresh and its filter is clean. These refill and filter options make it effortless to maintain peak air purification performance: removing 99.99% of dust and continuously producing fresh oxygen.Choose Your Refill Option 6-Month Algae & Nutrient Refill ($300) — Fresh live spirulina culture + full nutrient pack to sustain your OAK's living ecosystem for 6 months. 6-Month Refill + New HEPA Filter ($325) — The complete renewal bundle. Best value. New HEPA Filter ($50) — Standalone HEPA filter replacement. Recommended every 6–12 months. Compatible with OAK — The Liquid Tree only.