I'm just about to venture into the world of planted tanks and are looking for some advice on external filters. The tanks is 180ltrs.I'm currently looking at the Tetratec EX1200 as it seems to be superb value. I also have two spare externals: a 205 and a 305. I'm kinda hoping for peoples opinions on whether to get the new filter or use the one's i already have combined. Thanks for reading.