I just got this pretty little tank for a great price at my LFS...but now I'm wondering if it was so great because something is odd about it. (Tank: https://www.amazon.com/gp/aw/d/B007I951GO) It has a built-in filter. There is a line above the filter that says "water line," so I'm assuming that's where the water needs to be? I filled it up to there but it hardly disturbs the water at all with only very little current I can feel. There's not waterfall effect like with a HOB filter, because the water line is above the filter. Am I explaining it OK? I'm just wondering if anyone else happens to have this tank and if they might be able to tell me how strong their filter is. Or if I'm doing something totally wrong here.... ETA: Yes, it was me doing something wrong, not the tank. LOL I saw a pic someone had posted on another site of how they had set up their filter compartment: from the top down, they had a sponge, carbon, and ceramic media. I had mine the opposite way: ceramic media, carbon, a sponge: I always have he songs at the bottom of my HOB filters so I figured I'd do the same here. Apparently that is not correct. I flipped it all around so it was like the guy's photo, and BOOM, instant increase in filtration! Now it's actually moving the water nicely. So I'm just posting this in case anyone else is searching the Internet at 12:40 one night in the future and wondering why their AquaTop Zen Nano filter isn't doing much.