You should get an accurate PH reading on the water after about 24 hours, set out a glass and check the PH after it gases off and let us know the result.
What is really high? It shouldn't drop more that a full point.
If your fish are happy I wouldn't worry about it to much. It's not that your fish like a higher PH so much as they like water with higher total dissolved solids.
You can get crushed coral at any LFS
, Petco and Petsmart also carry it.