Stick with chlorine. Hydrogen peroxide is more trouble than it's worth.

Yes, technically you can use hydrogen peroxide as a pool sanitizer — but don’t expect it to work like a simple swap.

Hydrogen peroxide breaks down too fast in sunlight, so you either need a UV or ozone system to keep it active, or you’ll be dumping in new stuff constantly. It doesn’t leave a residual like chlorine does, meaning one rainstorm or heavy swim day and your pool is basically untreated. Also, the concentration needed is much higher than the brown bottle from the drugstore — you’re looking at food-grade 35% or stronger, which is seriously hazardous to handle.

For most backyard pools, chlorine is just easier, cheaper, and more forgiving. Hydrogen peroxide can work in commercial or very well-maintained setups with proper equipment, but for a weekend warrior? Not worth the hassle.

Save yourself the chemistry experiment.