Liquid chlorine for daily chores; calcium hypochlorite for the heavy stuff.

Depends on what you’re doing. Liquid chlorine (sodium hypochlorite) is the everyday workhorse. It’s cheap, mixes instantly, and doesn’t mess with your calcium levels. But it’s weaker (10-12% chlorine vs 65% in solid), loses potency over time, and you have to haul heavy jugs.

Calcium hypochlorite (the granular or tablet stuff) is concentrated and shelf-stable. Great for shocking a green pool. The downside: it spikes your calcium hardness and pH. If your water’s already hard, you’ll be battling scale. Plus, you need to pre-dissolve it or risk bleaching your liner.

For routine chlorination, liquid wins for simplicity. For a one-time kill shot after a party, reach for cal-hypo.

If your fill water is hard, stick with liquid and skip the calcium headache.