Southern Association of Colleges and Schools Commission on Colleges. Bob Jones University is a candidate for accreditation with the Southern Association of Colleges and Schools Commission on Colleges to award associate, baccalaureate, masters, and doctorate degrees.
hthÂ® calcium hardness increaser, 4 lbs. hthÂ® calcium hardness increaser, 4 lbs., is used to raise the calcium hardness of swimming pool water. Low calcium hardness may cause the pool water to be corrosive, resulting in damage to pool surfaces and equipment.
To increase calcium hardness you'll need calcium chloride. You can swim 2 hours after adding, but if you can, allow for one full turn-over of the water. A turn-over is a full and complete filtration of all of the swimming pool water, normally about 10 hours. This is why you'll want to make any adjustments at night. A pool shock is a different story.