REEF TANK LOG

The reef logbook that keeps your data.

Parameters, trend charts, dose schedules and a coral journal for saltwater tanks. Everything is stored on your device. No account, no ads, and logging is free forever.

It records what you measure - it does not tell you how to keep your reef alive. Target ranges in the app are common hobby reference bands, shown for orientation. Dosing, water changes and the health of your livestock remain your call.

What it does

Every parameter, at reef precision

Salinity to 1.0255, alkalinity, calcium, magnesium, nitrate, phosphate, pH and temperature. Tag each result with the kit you used - Hanna, Salifert, Red Sea or API.

A typo is never permanent

Open the reading history straight from the chart and edit or delete any single point. Entering 85 instead of 8.5 does not wreck the trend line for good.

The trend, not just the number

Charts with your target range shaded in, over 30 days, 90 days, a year or everything, with a stability readout for the window you are looking at.

Dose schedules that fire offline

Alk, calcium, magnesium and trace, daily, every N days or on chosen weekdays, with local reminders. Tick a dose off in one tap. (Pro)

A journal per animal

Corals, fish and inverts by common and scientific name, sorted into SPS, LPS, softies, fish and inverts, with a written journal to follow growth, colour and health.

Maintenance and equipment

Water changes with percentage and cost, skimmer services, glass cleans and media swaps. Lights, pumps, heaters and dosers with install dates and warranty notes.

Free and Pro

Logging and backup are free forever: one tank, unlimited readings, trend charts, the livestock journal, maintenance and equipment, and full backup and restore. Pro adds unlimited tanks and dose schedules with offline reminders.

Pro is $3.99 monthly or $19.99 yearly, or a $29.99 one-time lifetime purchase. Subscriptions renew automatically unless cancelled at least 24 hours before the current period ends; the lifetime purchase does not renew. Cancel in App Store settings, or in Google Play under Payments and subscriptions.

Support

Email [email protected]. A human reads every message. Tell us the device, the app version from Settings, and what you expected to happen. We answer within two business days.

My tanks and readings disappeared after reinstalling

Everything is stored on the device and is never uploaded to a server, so removing the app removes the data with it. Restoring a purchase brings Pro back, not the readings - which is exactly why Settings has an export. Keep a backup file somewhere off the phone.

I bought Pro and the app still shows the free limit

Open Settings and tap Restore purchases, signed in with the same Apple ID or Google account you bought with. If it still does not unlock, email us with the store receipt and we will sort it out.

A dose reminder never arrived

Reminders are ordinary local notifications. Battery saver, Focus modes, or a device that was switched off can delay or suppress them. Never treat a reminder - or its absence - as proof that a dose was or was not given.

Can I move my log to a new phone?

Yes. Export a backup on the old device, move the file across however you like, and use Restore on the new one. The file is a plain export you keep; there is no account and nothing to lock you out.

How do I delete my data?

Deleting a tank removes its readings, and uninstalling the app removes everything. There is no server-side copy to request the deletion of - see the Privacy Policy.