Should I use hydrogen peroxide instead of chlorine in my pool?

Stick with chlorine. Hydrogen peroxide breaks down too fast in sunlight, requires a UV or ozone system to stay active, and doesn’t leave a residual, so one rainstorm or heavy swim day leaves your pool untreated. You’d need hazardous food-grade 35% concentration, not drugstore stuff. For most backyard pools, chlorine is easier, cheaper, and more forgiving.