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Log a test in seconds
Quick mode for the basics, Full Test for all ten parameters — each field shows its optimal range while you type.
Fish Tank Tracker
Free on iOS & Android
Healthy tanks keep records.
Fish Tank Tracker is the lab notebook your aquarium deserves: log ten water parameters in seconds, watch the trend lines against optimal ranges, and get a nudge before maintenance slips. Reef, saltwater, freshwater or brackish — all offline, no account, no subscription.
works offline
no account
no subscription
every tank type
Straight from the app
Numbers become a story.
Every test you log lands on a chart with the optimal band drawn behind it. Tap a parameter — this is a month of a real reef diary.
How it works
Test. Chart. Correct. Repeat.
The whole loop of good fishkeeping, minus the wet notebook.
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Watch the trend
Charts plot every reading against the optimal band, so a slow drift shows up long before your fish complain.
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Correct with confidence
The dosing calculator starts from your latest test and your own target, and turns the gap into millilitres of the product you actually own — with a warning not to rush it.
The screens
One tab per job, zero clutter.
Dashboard, livestock, equipment and tools — everything else is one tap deep.
Dashboard
Your tank's vitals with color-coded status the moment you open the app.
Livestock
Every fish, coral and invert with species, photos, dates and health notes.
Maintenance
Recurring tasks per piece of equipment, with reminders when they come due.
Equipment
An inventory of lights, pumps, heaters and skimmers — with age and history.
Built for fishkeepers
Small app. Complete logbook.
Ten parameters
Temperature, salinity, pH, ammonia, nitrite, nitrate, alkalinity, calcium, magnesium and phosphate — with notes on every test.
Charts with ranges
Optimal, acceptable or critical at a glance — reef ranges for saltwater tanks, nitrogen-cycle checks for every tank, or target ranges you set yourself — and charted over 30 days, 90 days, a year or all time.
Livestock journal
Fish, corals and inverts with species, photos, purchase dates, cost and health status.
Maintenance reminders
Recurring tasks on your schedule — water changes, skimmer cups, filter floss — with local notifications when due.
Dosing calculator
Alk, calcium and magnesium doses for your exact volume and product — plus water change math.
Offline & private
The app keeps everything in a local database on your device — no account, no server, no tracking. Back it all up to a file and restore it on a new phone, free. Pro exports your test history to CSV.
Honest pricing
Free to run a tank. Pro to run a fish room.
No subscription and no ads in the app, ever. Pro is one purchase, once.
Free
Everything for one tank
The complete toolkit, sized for a single display tank.
- Full ten-parameter logging with charts
- A month of parameter history
- Five livestock entries
- Complete equipment log & maintenance reminders
- Water change log & dosing calculator
- Your own target ranges & full backups
Pro · one-time
Unlimited everything
For multiple tanks, long memories and spreadsheet people.
- Unlimited tanks — display, frag, quarantine…
- Unlimited parameter history
- Unlimited livestock
- Trend analysis — stability scores & direction
- CSV export of your water test history
One-time purchase, never a subscription. Longtime users keep the free quotas they installed under.
Questions
The short answers.
What tank types are supported?
Reef, FOWLR, freshwater, saltwater and brackish tanks all have a home. Reef and FOWLR tanks are checked against reef ranges, and every tank gets ammonia, nitrite and nitrate checks. There's an Other type for anything else wet.
Which parameters can I log?
Temperature, salinity (in ppt or specific gravity), pH, ammonia, nitrite, nitrate, alkalinity, calcium, magnesium and phosphate — with notes on every test. Quick mode logs the basics in seconds; Full Test covers all ten. Tests can be logged for an earlier day and edited later.
Is my data stored in the cloud?
No. Everything lives in a local database on your device. No account, no login, no server — the app works completely offline. To keep it safe or move to a new phone, back it all up to a file (to Files, iCloud Drive, Google Drive or email) and restore it there, free.
Is there a subscription or ads?
Neither. The core app is free, and Pro is a single one-time purchase that unlocks unlimited tanks, unlimited history, unlimited livestock, trend analysis and CSV export. No ads in the app, ever.
What does the free version include?
Everything you need to run one tank properly: full ten-parameter logging with charts, a month of history, five livestock entries, the complete equipment log, maintenance schedules with reminders, water change logging and the dosing calculator.
How do the reminders work?
Maintenance tasks repeat on the schedule you set — every 3 days, weekly, monthly or a custom interval — and the app sends a local notification when one comes due, plus an optional weekly reminder to test your water on the day and time you choose.
Your fish can't tell you the nitrate is creeping. Your charts can.
Free download. Works offline. Set up in a minute.