I have a small tank that has just finshed cycling with a fluval plus 1, shortly it will be housing acouple of BNs, but iv been reading instructions for this filter and is says to remove the filter and and the new one every 3 to 6 months... as its a single filter in it, all the bacteria well be jist removed. So it says suppliment with stuff to return the bacteria; but do you tjink it would be better to cut both the new and old medium in half and change only half every 1 to 2 months... to me this seems tje better idea. What do you think, cheers guys