My 180l Juwel Rio has been cycling for nearly 5 weeks now and I've put some minnows in. It is quite heavily planted and I'm waiting to see which plants will be successful. At this stage, some of the plants are establishing themselves (one has died) and some leaves are dying and coming off - just what I'd expect. My problem is that there is a 'dead zone' where the water doesn't seem to circulate and any dead leaves accumulate here. It's an area about three inches square at the bottom of the filter box. It worries me that when the tank is more established with more fish then lots of waste will build up here. Obviously I'll take care to clean the gravel here more often but does anyone have any other suggestions to circulate the water better? I've got an airstone from an old tank, any good? Thanks!