Biomaster 250 in a rio 125 cabinet. This is the older style one that is not full width, vs the new style that has cabinet doors under the whole way across. Door shuts fine. The shelf has to be removed. Again I'm not sure if the newer cabinets have removable shelves. I'm sure Google or someone on here will know.
Personally I wouldn't get the 250 for a 180 litre tank. The flow won't be enough.