I know there's a lot of debate about how good these are, whether they flow as much as some other brands...but honestly...there's no real way to measure flow rate of a pump that's designed like this. It's not like you can put a hose in a bucket and time it to see how much it puts in the bucket. About all you can do is just watch it and see what it does.
So, I made this short video. This is in my 220g (6ft long) tank. I turned off all other powerheads for this video, and have since left them off. This and the return pump are the only flow in the tank. The WP40 is at one end, and this overflow box is at the other end. As you can see, I'm getting waves in excess of 1". I had to adjust it a bit because I was getting splashing noises as it was hitting the center braces of the tank.
[video=youtube;Fcfvv4ssLko]http://www.youtube.com/watch?v=Fcfvv4ssLko[/video]
So, I made this short video. This is in my 220g (6ft long) tank. I turned off all other powerheads for this video, and have since left them off. This and the return pump are the only flow in the tank. The WP40 is at one end, and this overflow box is at the other end. As you can see, I'm getting waves in excess of 1". I had to adjust it a bit because I was getting splashing noises as it was hitting the center braces of the tank.
[video=youtube;Fcfvv4ssLko]http://www.youtube.com/watch?v=Fcfvv4ssLko[/video]


