Hot Tub Chemical Calculator

Hot Tub Chemical Calculator keeps water-test readings, transparent dose estimates, and routine care in one calm local log.

Set up your tub volume, then record the chemistry you actually test: pH, total alkalinity, sanitizer, calcium hardness, temperature, and notes. Review the latest snapshot from the dashboard, compare readings over time, and reopen saved tests or dose details whenever you need them.

The built-in alkalinity and calcium-hardness calculators keep the important context visible: tub volume, current and target readings, product label rate, strength, amount, units, formula source, rounding, and assumptions. Results are estimates—not a certification of water condition. Product labels and manufacturer directions always take precedence.

Stay organized with:
• Fast water-test entry
• A searchable hot tub chemical log for tests and doses
• Chemistry trends with target context
• A practical spa maintenance log with recurring tasks
• Optional maintenance notifications
• CSV export through Android's document picker
• Valid local backup restore and delete-all controls
• Light, dark, US, and metric display settings

The free app supports one tub, complete core logging, both built-in calculators, 30-day trends, basic reminders, CSV export, restore, and delete-all controls.

Hot Tub Chemical Calculator Pro is a one-time Premium unlock. It adds multiple tubs, per-tub custom target ranges, saved custom products and supported label rates, longer trend ranges, advanced reminder recurrence, PDF service history, and local backup creation. It is not a subscription, and the app contains no ads.

This focused spa chemical calculator is built for hot tub owners who want quick calculations and durable records without an account-first platform. Your records stay on your device unless you explicitly export or back them up. There is no PatchMedia cloud sync, analytics SDK, or advertising SDK.

Hot Tub Chemical Calculator is an informational utility. Always follow product labels, test between adjustments, and use local professional guidance when needed.

Recent changes:
Meet Hot Tub Chemical Calculator, a private local-first water care log. Record pH, alkalinity, sanitizer, hardness, temperature, dose inputs, notes, and treatment outcomes. Review trends, calculate transparent volume-aware alkalinity and calcium-hardness estimates, and manage recurring care with optional reminders. Export CSV; Pro adds multiple tubs, custom targets and products, longer trends, PDF history, advanced reminders, and local backups. Always follow product labels.