The Fluval FX series stands for high-performance and reliability. Made in Italy, the FX4 canister filter is a compact counterpart of the FX6. FX4 is suitable for those upgrading from Fluval 406. Fluval FX4 is recommended for both freshwater and saltwater aquariums up to 1000 L (250 US Gal).
Fluval FX6 is a high-performance external canister filter for both fresh water and salt water aquariums up to 1500L. Has an astounding filter media capacity that produces the cleanest and healthiest results ever.