Two Little Fishies PhosBan Reactor 550

The PhosBan Reactor 550 is designed with the upflow principle to achieve the most efficient use of PhosBan® or other chemical filter media. By pushing
water from the bottom upward through a dispersion plate, it forces an even
distribution of water through the media, and prevents channeling. It can be
mounted hanging on the back of the aquarium or below the aquarium. Includes ball valve for regulating flow, and flexible connection fittings that rotate 180 degrees to allow a perfect custom fit to your installation. The threaded lid design makes servicing quick and easy. One reactor for aquariums up to 600 gallons / 2271 litres.

Refer to PhosBan Reactor 150 link for operating instructions on the 150, general principle is the same, just the quantities will alter for the 550.