We have falls and a spitter as well. I figured the guy was probably trying to sell me some high pricced gizmo. Thier pond equip is about 4x's higher than anywhere else, butthey have great plants at reasonable prices....go figure!
I read some info that says the extra air will help with algae and muck on the bottom, guess it wouldnt' hurt, but I can probably get away without it. Our new 31" wier jsut came yesterday, so when we get another falls/stream going it should be plenty.