Thanks jolliolloi. I must admit I haven't seen the Vision 450 but was pleased to see that it stood higher than the smaller models. This is one thing that the Aqua Ones have over most Juwels. Why both filters? The internal filter is not particularly nice to look at and if we choose a large cannister I can't see that we need the internal, but will pass on any comments to the client who wants the usual community tropicals - angels etc. We usually prefer Eheim filters over anything else for reliability, quality, long life, speed of cleaning. The Aquience comes with a filter which we could change but also has T5 lighting which would be nice.