i payed $75 for a 50lb bag i feel like i got robbed. went to local pool store because it is conveinent closed lowes or hd is 1/2hr ride vut that just sounds like alot. that said they tested water and came up almost exactly with waht i did and my water is looking great today after adding the cacium. ch was 80 50lbs raised to 180 overnight added 25lbs today to raise it