With 17,280 gallons, 3 quarts is 2.6 ppm per day of Cl lost. I lose 2 - 3 ppm per day from my pool, and it's 36,000 gallons, so that's one big jug of Cl (1.42 gallons) per day...

I read someone else posted on here the other day that they thought 2 ppm per day was normal.