CYA between 60 and 70 isn't a serious problem. It will come down over time as water gets replaced.
Just keep the FC level between 5 and 9, and never below 5, and you should be fine.
It seems likely that there are less than 18,000 gallons of water actually in the pool, even if the pool could hold that much water. 54" is a common wall height, but it is rare that the water is actually filled up to that level.