*Product May Be Subject To Extended Lead Times. The UltraZap Gravity Filter 15W / 50 Litre offers a powerful, two-stage filtration system designed to keep your pond water clear, healthy, and biologically balanced. Water first passes through a built-in 8W UV clarifier, which helps eliminate algae and harmful microorganisms, improving water clarity right from the start. It then flows into a biological chamber filled with specially-developed bio balls that provide optimal surface area for beneficial bacteria to thrive. These bacteria work continuously to break down toxic ammonia and nitrites, converting them into less harmful nitrates through natural biological filtration. The combination of UV sterilization and bio-filtration ensures cleaner, clearer water while supporting a stable environment for fish and plants. Compact and efficient, this filter is perfect for small to medium-sized ponds and offers low-maintenance operation with high performance. Pond Cap 10000 L and 500 Bio Bals