I was looking to replace my current Hydromatic SKV50 pump and noticed that the performance data is way different than many other pumps: GPH @ 10': 9480 GPH @ 15': 6000 Other 1/2 HP Pumps Liberty LE51A GPH @ 10': 6720 GPH @ 15': 5400 PHCC E7055NS GPH @ 10': 4680 GPH @ 15': 3960 Zoeller M267 GPH @ 10': 5340 GPH @ 15': 3000 Motor RPMs seem to all be the same. Could it be the size of the impeller that contributes to the large differences? How is it that the Hydromatic is 2000 more GPH? I'm looking for a replacement pump for a Bathroom w/ toilet/shower/sink, Washer, and Wet Bar Sink. Should I stick with the Hydromatic, or would I be ok with the Liberty?