Frost: Cold Plunge Care

Pay once. No subscription, no ads, no account. Works offline.

Frost is the iOS cold plunge water-chemistry assistant. Enter your sanitizer and pH readings, get exact doses scaled to your plunge's volume. Whether you run chlorine or hydrogen peroxide, Frost gets the math right — and warns you before the two ever meet.

Features
• Dual-path sanitizer math: chlorine (Dichlor 56%, Cal-hypo 68%, liquid 12.5%) or hydrogen peroxide (3% household, 35% food-grade)
• Drain-required safety interlock when switching sanitizers — chlorine and peroxide chemically neutralize each other
• Handling advisory for 35% food-grade peroxide (gloves, eye protection)
• Tub-type-aware water-change cadence — chillers vs DIY chest-freezer builds get different intervals
• Symptom-first cloudy-water diagnostic — "Water looking off?" is the hero card, not a buried sub-screen
• After-session top-up doses based on people × sessions
• Filter rinse, deep-clean, and replace cadence tracking
• Cold-water test-strip context — strips read slowly below 50°F
• Locale-aware metric/imperial units (liters or gallons), comma-decimal input supported
• Universal app for iPhone and iPad

For cold plungers running 80–120 gal / 300–450 L home setups — chiller-based, DIY chest-freezer, or somewhere in between.

$3.99 one-time. No subscription, no ads, no account, no cloud.

Privacy: Frost collects nothing. No analytics, no accounts, no network requests. Your settings live on your device.