TankDiary is a private logbook for freshwater and planted tanks. Parameter charts that show drift before it costs you fish. Reminders that fire. A journal you'll actually keep.
Free to start. $24.99 once. No subscription.
Living Room 20g
Parameters
Why this exists
A notebook can't warn you nitrate has been creeping for three weeks. And the old aquarium apps want $40 a year to remember your KH.
A damp notebook, a spreadsheet with 40 columns, or a ten-year-old app built for reef keepers that charges monthly and still loses your data in a sync bug.
Freshwater-first defaults, charts that flag drift, reminders that fire on time. Buy it once. Your data stays on your phone, exportable any day you want out.
What it does
Thirteen parameters, charted. The safe range is drawn behind the line, so a nitrate creep or KH crash is obvious at a glance. Ranges are editable per tank.
pH — 3 months
One sheet, one date, every value you measured. Water change done? That's one tap. The parameters you actually use float to the top.
Add Readings
Water changes, filter cleans, ferts, trims. Set the interval once; TankDiary nags you at the hour you choose and reschedules when you check it off. Dosing tasks remember the product and the dose.
Maintenance
A photo grid of your livestock and a journal for milestones — first berried shrimp, the big rescape, the day the carpet finally filled in.
Livestock
Pick the shrimp profile and safe ranges snap to Neocaridina numbers — GH 4–8, KH 0–4, TDS 150–250, 68–75 °F. Not reef numbers with the salt removed.
Safe Ranges — Shrimp
Privacy
No account. No cloud. No analytics. The App Store label says "Data Not Collected" because there is nothing to collect.
Test water in the fish room with no signal. Everything works. There is no server to be down.
One file with every tank, reading, and photo. AirDrop it, stick it in Drive, keep it on a USB stick. Restoring it is one tap.
Full CSV export is free, forever. Your five years of logs will open in any spreadsheet.
Pricing
Once.
$0
forever
$24.99
pay once, yours forever
Prefer small payments? There's a $9.99/yr option in the app. Honestly, the lifetime is the better deal.
Completely. There is no backend — the app never makes a network request except when you buy or restore a purchase through Apple.
Not yet. TankDiary is native SwiftUI, iOS 17 and up. If it earns its keep on iOS, Android is the obvious next step.
It's on your phone, not our server (there is no server). You can export everything as CSV or as a single backup file whenever you like — both are free-tier features on purpose.
Yes — salinity, alkalinity, calcium, and magnesium are all in there with brackish, saltwater, and reef range defaults. But the app is designed freshwater-first; if you want dosing calculators for a mixed reef, dedicated reef apps go deeper.
Because a logbook has no server costs and shouldn't rent itself to you. $24.99 once covers the development. If that model dies, worst case: the app stops getting updates and keeps working, with your data exportable. A dead subscription app just locks you out.
Not yet — export is CSV, import is on the roadmap. Most people find that after one week of one-tap logging, the spreadsheet retires itself.
Free to start. $24.99 once. No subscription. Ever.