May I just chime in here to say I think your pH reading of 9.47 for your tap water is not right. Impossible they would let water from your tap be that high.
Our tap water here is somewhat hard, and alkaline too but the water treatment plant doesn't let the pH go higher than about 7.6. Our well water, straight from the limestone aquifer, untreated, comes in at around 8.2. You can test your tap water yourself using a swimming pool test kit to get an accurate reading. Or take a water sample in a ziploc bag to any pool store for testing.
