Hi I wonder if anyone can help I recently purchased trigon 350 corner tank with cabinet I've upgraded from a small basic 190 fish tank to this beast of a tank can anyone help me and advise me what size filter I have in this thing as I need to buy replacement lid and it did not come with it as previous owner lost it I'm not too sure if it's a sixth or 8 bioflow I would appreciate it if someone could help me out on this