I've got two whisper 150s that each run into one end of a small pipe with five outlets with on/off handles; Two are closed, the other 3 are lines feeding these (in a 72gal bowfront). You kind of have to orient them so that the end is the upmost part and the part where it connects to the airline is the lowest, otherwise bubbles only come out about halfway down the stone. Still a lot of bubbles, just annoying to have to go shoulder-deep in the tank to rearrange them after the pleco re-rearranges them for the third time this week. I think I'm going to bury them in the substrate next time and see how that works out. Each of the 3 is effectively running on 66% of a whisper 150 and that definitely helps, but I think if you had a smaller pump instead of two heavier-duty ones you probably want to go with short bars or a round bubble stone instead. I actually got two packs so I could use one in each of me sit-and-let-it-dechlorinate buckets, and they run off a single whisper 150, which is good enough for a 5 gal bucket.Basically they're pretty good if you know how you're going to be using them and have a decent amount of air pressure, but for smaller tanks and smaller airpumps the longest ones are going to be overkill and you should be looking for a 4"-6" bar or a couple of round bubble stones instead.