Hi Richard. The Jebao 404 is currently £50 at Kettering Koi. You get 1200 litres per hour on a 16/22 outlet that includes a flow controller, all pipework and tubing. You can have savage rolling currents one day, and a gentle trickle the next. I also find the larger size lily pipe (22mm as opposed to 16mm) have my kind of flow dynamics, so you might want to make a choice on inlet and outlets. I think I got 10 litres of dry pumice in mine, which isn't bad at all. It's a very decent size. I love it.