A slow dissolving unstabilized chlorine in powder or granular form. It has minimal impact on pH but it will raise calcium hardness with continued use. Suitable for normal sanitation or SLAMing and is the most common form of chlorine sold as “Shock”. It can cloud your water if your TA is high and it is recommended to premix it in a bucket of water before adding to your pool. Relatively inexpensive. It is sold in different strengths with 48% and 65% being the most common. 2.5 oz of the 65% stuff will raise 1000 gallons 1 ppm FC.