Its shown in the Eheim listing. They make an aquaball without the filter canister, its shown as the all grey unit in the photos. You could run either (with or without filter) as I think they're the same. The flow rate on the largest isn't that high so you could run that one on yor tank though it does depend on what other filters & stuff you're using. I'd avoid the others, neither are names i've seen before but I must admit I'm not familiar with all the equipment sold int he UK. The biggest concern about using off-brnad stuff from e-bay is about getting parts in the future should you need them. A quality unit like the Eheims will usually last long enough that you'll need replacement parts for something in the future, the others usually don't last long enough to need replacement parts but you spend more buying a second unit and usually they fail at the most inopportune times.