Read the label, then do the math.

Yes, you need to calculate your pool volume. Algaecide doses are based on gallons, not pool size vibes.

Measure your pool. Rectangular: length × width × average depth × 7.5 = gallons. Circular: diameter × diameter × average depth × 5.9. Kidney shape gets trickier, but there are free online calculators that do it for you.

Once you know your volume, check the algaecide label. Most brands say something like “1 quart per 10,000 gallons.” Stick to that. Twice as much doesn’t mean twice the algae killing—it can foam up your pool or mess with your chlorine.

Also worth noting: different algaecides treat different problems. Copper-based kills stubborn algae but can stain. Polyquat is gentler and won’t cloud. Pick the right one for your issue, then dose by the numbers.

This is one of those places where guessing costs you money and time.