For a large pond, you really need a pump that can handle a high flow rate without burning out. I had a similar situation and decided to go with an external pump from Streamline Pump Solutions. When you buy external pond pump https://streamlinepumpsolutions.com.au/product-category/pond-pumps/ , their options are perfect for bigger setups. For example, their RHMS46 Multistage Pressure Pump is ideal for large ponds—it moves up to 350 liters per minute and has the power to push water over long distances, which is exactly what I needed for my waterfalls. Plus, it's built for durability, so it can handle the demands of a large pond system without needing constant maintenance. Streamline’s pumps are efficient and designed to keep things running smoothly for the long haul.