I have decided to go w/ the 3+ just because I like more filtration than needed, my tank is going to be a 20 long. I have a eheim 2217 on my 75g and love it, but am not going to buy an external canister for a 20. My next choice would be a power filter but since I am going to put it in a planted tank I can not use activated carbon. Soooo that leads me to this choice s ince I hate UGFs. Does it distrub the water surface well? I am not going to have a large bioload. Just two german blues, a school of cardinal or neons, 3 panda corys and a few ottos so I dont need anything to powerful