TankDiary: Aquarium Tracker
Cycle & Water Test Tracker
About
Easily track aquarium water parameters, schedule maintenance, and monitor your tank's health. This app helps you understand your tank's cycling stage and provides reliable reminders for water changes and other tasks. It offers detailed logging and historical charts for long-term trend analysis.
What's New in TankDiary
1.4.0
September 11, 2026
Log a water test the way you actually read it. • Test-kit color chart — the Add Readings sheet now shows the liquid-kit color card for ammonia, nitrite, nitrate and pH. Tap the square that matches your test tube and the reading is logged. Follows the API Freshwater Master Test Kit steps; other liquid kits use the same values. Switch it off anytime if you'd rather type. • Cleaner entry — parameters your tank doesn't use stay out of the way until you ask for them. • Full German, Japanese and Brazilian Portuguese, and units that follow your region. • Fixed: readings and chart chips could appear in a different order every time you opened a tank. The color chart, the cycle tracker and the calculator are free — no Pro required.
MoreSubscriptions & In-App Purchases
TankDiary Pro — Yearly
Unlimited tanks and full history, billed yearly.
Developer apps
FAQ
How does TankDiary help with cycling a new aquarium?
TankDiary reads your ammonia, nitrite, and nitrate test results and identifies the current stage of your tank's nitrogen cycle. This helps you know when it's safe to add fish.
Can I track multiple aquariums with TankDiary?
The free version of TankDiary allows you to track one tank. TankDiary Pro, available as a one-time purchase or yearly subscription, unlocks unlimited tanks.
Does TankDiary require an internet connection?
No, TankDiary is designed to work entirely offline. All your data is stored locally on your device, ensuring privacy and accessibility without an internet connection.
What kind of maintenance reminders does TankDiary offer?
TankDiary provides reliable local reminders for water changes, filter cleans, dosing, and trimming. You can set custom schedules to ensure your tank receives timely care.
How does the water change calculator work in TankDiary?
The built-in water change calculator helps you determine the amount of water to remove and the correct amount of water conditioner to add. It also estimates the impact on your nitrate levels, considering your tap water's nitrate content.
What data can I log in TankDiary?
You can log a comprehensive range of parameters including temperature, pH, ammonia, nitrite, nitrate, GH, KH, and TDS. The app also supports logging livestock with photos and maintaining a photo journal for tank milestones.
What are the pricing options for TankDiary?
TankDiary offers a free version with core features for one tank. TankDiary Pro is available as a one-time purchase for unlimited tanks and full history, with a yearly subscription option also provided.
Is TankDiary suitable for beginners?
Yes, TankDiary is designed for aquarium hobbyists, including beginners. Its clear interface, color-coded safe ranges, and cycle tracking features make it easier to manage a new or established tank.
