Quicker dissolve (as compared to plain medium grain salt). Fine grain. High purity. All natural. Fully dissolves in less than 3 minutes (as compared to medium grain salt. 1 Based on internal laboratory testing. 2 Always refer to your system's manual. 3 Gallons approximated using standard pool dimensions and pool depths of 4 inches shallow end to 7-9 inches deep end. One 40 lb bag of Professional Choice Pool Salt raises the salinity level of 10,000 gallons of water by 480 ppm). Keep your pool clean and sparkling with Morton Professional Choice Pool Salt. We've improved pool maintenance with our fine grain salt that dissolve quicker so you can enjoy your pool sooner. It's what you expect from Morton - a brand you trust. How much salt do you need? To Reach target level of 3500 sq ppm. Current Level: 0 ppm: 8 bags 12 in x 24 in (9500 - 11000 gallons); 11 bags 14 in x 28 in (13000 - 15000 gallons); 11 bags 15 in x 30 in (13900 - 15200 gallons); 15 bags 16 in x 32 in (17300-20000 gallons); 18 bags 18 in x 36 in (22500-24500 gallons); 20 bags 19 in x 39 in (24400-27500) gallons; 25 bags 20 in x 40 in (30000-40000) gallons. 1000 ppm: 6 bags 12 in x 24 in (9500 - 11000 gallons); 8 bags 14 in x 28 in (13000 - 15000 gallons); 8 bags 15 in x 30 in (13900-15200) gallons; 10 bags 16 in x 32 in (17300-20000 gallons); 13 bags 18 in x 36 in (22500-24500 gallons); 14 bags 19 in x 39 in (24400-27500) gallons; 18 bags 20 in x 40 in (30000-40000) gallons. Current Level: 2500 ppm: 2 bags 12 in x 24 in (9500 - 11000 gallons); 3 bags 14 in x 28 in (13000 - 15000 gallons); 3 bags 15 in x 30 in (13900 - 15200 gallons); 4 bags 16 in x 32 in (17300-20000 gallons); 5 bags 18 in x 36 in (22500-24500 gallons); 6 bags 19 in x 39 in (24400-27500) gallons; 7 bags 20 in x 40 in (30000-40000) gallons. Make sure to test your water regularly to maintain a target salt level.