My builder is telling me that the 1/2 HP deep well pump I purchased will not work in my well - he says I need a 3/4 HP pump - my ex-builder fiancee says a 1/2 HP will work fine. I need an unbiased answer: the well diameter is 6 1/8"; well casing diameter is 6 5/8"; static water level is 100'; pumping rate is 9 GPM; total well depth is 225'; the water will be for single household use. Please help!