In answer to a few questions,
cold water sterilising tablets will not clear the minerals,
boiling will not get rid of the minerals,
more and more Turks are drinking bottled water,
It is a regional problem, look around at the high number of renal clinics in this area,
Efes is not brewed in this area so is perfectly safe to drink.
As adults you are quite entitled to play Russian Roulette with your health.
If you have children then for the sake of a few lira you can save them from a lot of possible pain.