So my QT is this- 15 Gallon Aquarium » Aqueon® 15 Gallon Column Deluxe Aquarium Kit | PetSmart Which is a 15g column tank, with a QuietFlow filter 10 and one T5 bulb socket. I upgraded the heater as I did not like the one it came with. I cycled the tank about 2 months ago. First thing. Should this filter be adequate for a QT/HT? Do I need to add anything for flow? The filter provides a bit of flow, but not much at all. Last time I did water testing on the tank it had zero ammonia, zero nitrites and some nitrates (about 1.5-2weeks ago). I have since done a 20% WC but I have not retested the water yet. How can I check that the tank is still cycled? I know a sort of odd question. The tank has no substrate or rock. All it has is one large barnacle. The filter has a video about changing the cartridge and the only thing is my biological media is not built up like theirs is yet, so I worry about changing the cartridge. Could I put a cartridge in my DT sump to seed it just in case? How long would I need to leave it in the sump for? If I need to upgrade the filter, I am not too worried, would appreciate some suggestions if that is the case.