Liquid chlorine vs calcium hypochlorite: Liquid wins for daily use, cal-hypo for heavy shock treatments

Liquid chlorine (sodium hypochlorite) is the everyday workhorse—cheap, mixes instantly, and won’t mess with calcium levels, but it’s weaker (10-12% chlorine vs 65%) and loses potency. Calcium hypochlorite is concentrated and shelf-stable, great for shocking a green pool, but it spikes calcium hardness and pH, risking scale if your water’s already hard. For routine chlorination, liquid wins for simplicity; for a one-time kill shot, reach for cal-hypo. If your fill water is hard, stick with liquid to skip the calcium headache.