I've always felt the 150 was a little too strong for a normal 10 gallon but with marineland jumping the flow rates on the Penguins we're running out of good alternatives under that.
My instinct says go with the Whisper but at the same time I'm out of touch with the generic labeling. Is the 5-15 equal to the Whisper E, Jr, C 1,2,3,4 or 5? I heard the E is out of production now so I'm guessing it's the generic packaged equal to either the Jr or the C which either should be fine but I prefer the larger bag on the C if given a choice.
Life would be so much easier if everyone would stop changing names.