The Nu-Clear Model 1547 Extension Kit doubles the height of the Nu-Clear filters, allowing the use of twice as many bio balls. The extension kit for the Model 547, Biological Filter w/ Bio Balls includes bio balls. It expands the capability of the Model 547 Canister Filter so it can handle freshwater and saltwater fish-only tanks up to 180 gallons and ponds up to 600 gallons.
All extension kits include the body extensions, stainless steel band clamp and 1" mpt port plug. Extensions kits include a plug for the redundant inlet on the bottom filter. It is not recommended to mix different types of cartridges or media (i.e. Do not use a Model 547 with Extension Kit 1522, only use the Model 547 with the 1547 Extension Kit).