that was my main concern really, removing the old filter before i put the U2 in and the U2 not having a ful compliment of BB. the one i have at the moment is a HOB
filter that came with the tank so its ok, but doesnt seem too great, doesnt seem to get much of the suspended detritus out of the tank, most ends up settling on the plants leaves n such.
i dont think i would be able to put my media from my old filter into the new one, i can give it a go but i dont think it will.
my idea overall for this little endevour is to get rid of the HOB
filter so i can move my heater closer to the middle of the tank (where my HOB
filter is now) which frees up some space so i can put the U2 near the front of the tank as such and this should hopefully do up the circulation of the tank so not as much crap ends up on the gravel, but at the same time wont move the surface too much for my betta