Hi, I have an Eheim 2213 external filter and the standard Juwel filter in my rio180. I think the Eheim is supposed to be 400 l/ph, but that would imply it would fill a pint glass in about 5 seconds. I think the flow on mine might be a quarter that level at best. It's also making the occasional "clackety" sound. I have it about half full of that ceramic media (effitech? or something like that), then one "scrubber", a coarse blue sponge and then one of the white "wool" filters (in that order from the bottom). I'm guessing something needs to be replaced or I need to remove some media. I have the filter outputting into the Juwel filter box. Any ideas on how to improve things? More expense may result in divorce!!