Keep paper if you log once a month and enjoy the ritual. Switch when you have more than one tank, when you have missed a water change, or when you needed to know what nitrate was three weeks ago.
| Paper logbook | FishTank Diary | |
|---|---|---|
| Entry speed | Write by hand | Prefilled checklist, ~20 seconds |
| Reminders | None | Per-tank schedules, overdue surfaced |
| Trends | Read back through pages | 7 / 30 / 90-day chartsPro |
| Multiple tanks | Second notebook | Separate logs + All Tanks viewPro |
| Searching old readings | Flip pages | Filter by tank and date |
| Water damage | Real risk in a fish room | Device-only |
| Cost | A few dollars | $3.99 once |
| Works offline | Always | Yes |
Most aquarists start with a notebook, and the notebook does one thing better than any app: it never asks you to log in. That is why the app is built offline with no account — the notebook’s only real advantage should not be the reason you go back.
Where paper genuinely wins
- You write faster than you tap when you are testing with wet hands.
- No battery, no device, no update that moves a button.
- It sits next to the tank, which is where the tests happen.
Where paper stops working
Paper cannot tell you that the water change is due tomorrow. It cannot show a nitrate slope. And it cannot answer the only question that matters during a problem — what was different in the two weeks before this started? — because answering it means reading sixty pages of numbers in the order you wrote them.
