*Product May Be Subject To Extended Lead Times. The UltraZap 10L Bio Ball Filter and 15W UV Steriliser Combo is a powerful and efficient filtration solution designed for medium to large ponds, koi ponds, or aquaculture setups. This comprehensive system combines the best of both UV and biological filtration to maintain crystal-clear water and a healthy aquatic environment. The 15W UV steriliser effectively combats algae, harmful bacteria, and pathogens, preventing green water and ensuring your pond water remains clear and free from microorganisms. After UV treatment, the water flows through the 10-litre bio filter filled with premium bio balls, which provide an optimal surface area for beneficial bacteria to break down harmful ammonia and nitrites into safer nitrates. This combination of UV and biological filtration ensures superior water quality with minimal maintenance, making it the perfect choice for larger ponds. Pond cap 5000L