The best reef tank tracking app depends on how automated your tank is. If you run a Neptune Apex or another controller, Reef Trak or Aquarimate can pull that data in beside your manual tests. If you want AI help reading your numbers, NextUpReef does that on a subscription. If you want to log alkalinity, calcium, magnesium and nutrients privately and watch the trend lines, Fish Tank Tracker does it offline with no account.
One caution before the list. Much of what’s published comparing reef apps is written by the app makers themselves, Reef Trak and NextUpReef included, so weigh their rankings accordingly.
What makes a good reef tank tracking app? #
A reef needs more logging than a freshwater tank. Corals use up alkalinity, calcium and magnesium every day, nitrate and phosphate need to stay in a narrow band, and salinity rises as water evaporates. The features that matter:
- Fast entry for alk, calcium, magnesium, nitrate, phosphate and salinity. If logging a test takes longer than running it, you’ll stop.
- Charts with target bands. A week of alkalinity readings swinging 1 dKH a day tells you far more than any single reading.
- A record of doses and water changes, so you can tie a jump in a reading to what caused it.
- Reminders for tests and chores, like skimmer cups and filter socks. Our guide on how often to test reef tank water covers sensible intervals.
- Controller and ICP imports, if you use them.
- Clear data ownership. Know where your data lives and whether you can export it.
Reef tank tracking apps compared #
Prices are correct at the time of writing. They change, so check each store listing.
| App | Platforms | Price model | Controller imports | Where your data lives |
|---|---|---|---|---|
| Reef Trak | iOS, Android, web | Free core, $9.99 lifetime upgrade (per its developer) | Apex, HYDROS, Alkatronic, Mastertronic, AquaWiz (read-only) | Synced with a web portal |
| NextUpReef | iOS, Android | Free core; Pro $4.99/month or $39.99/year | Neptune Apex (Pro) | Account-based |
| Aquarimate | iOS, Android, Mac, Windows | $9.99 app; optional Live sync $9.99/year | Apex, Trident, Trident NP; Hanna Marine Master tester | On the device, or in the cloud with Live |
| Fish Tank Tracker | iOS, Android | Free for one tank; one-time Pro | None | Only on your phone |
| Apex Fusion | Web, iOS, Android | Included with Apex hardware | Apex only | Neptune’s cloud |
| A spreadsheet | Anything | Free | Manual | Wherever you save it |
1. Reef Trak: best for controller owners #
Reef Trak says it covers 55+ parameters, dosing logs tied to parameter trends, livestock and equipment records, maintenance schedules, photos, ICP results and reports. Its standout feature is read-only imports from Apex Fusion, HYDROS, Alkatronic, Mastertronic and AquaWiz, which puts controller readings next to your hand tests without handing Reef Trak control of any equipment. It runs on iOS, Android and a web portal. The developer lists a free core with a $9.99 lifetime upgrade and no subscription.
Wrong for: people who want their data kept only on their own device, since the portal and sync mean it lives with the service. If you test four parameters by hand and own no controller, most of what makes it special goes unused.
2. NextUpReef: best for AI analysis #
NextUpReef is free for its core: parameter logging with target ranges, a Reef Score and a Stability Score, 7, 30 and 90-day charts, and push reminders for chores like water changes and filter socks. Pro costs $4.99 a month or $39.99 a year after a 30-day trial. It adds an AI advisor and chat, AI photo logging that reads values from a picture of your test kit, Neptune Apex integration, multiple tanks and longer history views.
Wrong for: anyone with more than one tank who doesn’t want a subscription, and anyone wary of scores. A Reef Score summarizes your logging and readings. It isn’t a diagnosis, and a tank can score well while a coral is struggling.
3. Aquarimate: best for Hanna Marine Master users and desktop logging #
Aquarimate has been around since 2012 and is the only app here with native Mac and Windows versions. According to its App Store release notes, it can import results from Hanna’s Marine Master multiparameter tester and supports Apex, Trident and Trident NP controllers across multiple tanks. It also offers timestamps so you can log more than one test a day, the Aquaribase species library, expense tracking and photo galleries. At the time of writing it’s a $9.99 paid app, and the optional Aquarimate Live cloud sync is $9.99 a year.
Wrong for: anyone who wants to try before paying, and keepers who want a lightweight phone-only log.
4. Fish Tank Tracker: best private, offline log #
Fish Tank Tracker is the simplest option here, on purpose. You log up to ten parameters per test: temperature, salinity (ppt), pH, ammonia, nitrite, nitrate, alkalinity (dKH), calcium, magnesium and phosphate (ppm). Quick mode covers the basics and Full Test covers all ten. Each reading is color-coded and charted against a reef optimal band (alk 8 to 11 dKH, calcium 400 to 450, magnesium 1,300 to 1,400, nitrate 0 to 10, phosphate 0 to 0.1). Recurring maintenance tasks attach to each piece of equipment, such as a skimmer cup every 3 days or filter socks weekly, and a local notification arrives when one is due. The livestock journal takes fish, corals and inverts with photos, purchase dates and cost. Everything stays on the phone, with no account and no ads.
The free tier covers one tank, a month of history and five livestock entries. A one-time Pro purchase adds unlimited tanks (useful for a frag or quarantine system), unlimited history, trend analysis with stability scores, and CSV export.
Wrong for: controller owners (there are no imports), anyone who tracks trace elements or ICP results (there are only the ten fixed fields), and anyone who wants the same data on two devices. There’s no dedicated dosing log either, so doses go in the test notes. Phosphate is entered in ppm, so Hanna ULR phosphorus readings need converting first (multiply ppb by 3.066, then divide by 1,000).
5. Apex Fusion: best if you already own an Apex #
Neptune’s Fusion is the controller’s own software. It records probe data such as pH, temperature and salinity around the clock. It also takes timestamped notes and manual test entries, and it logs Trident alk, calcium and magnesium results if you own one. As a log it’s solid, and it costs nothing extra if you have the hardware.
Wrong for: anyone without Apex hardware, and anyone who wants one place for readings from other brands’ testers.
6. A spreadsheet: best for ICP and custom analysis #
If you run ICP tests every few months and track 30 elements, a spreadsheet is still the most flexible tool. It won’t remind you of anything, though. Our spreadsheet vs app comparison includes a column layout you can copy.
Which reef tank app should you pick? #
| Your situation | Best fit |
|---|---|
| You run Apex, HYDROS or Alkatronic and want everything in one app | Reef Trak |
| You want AI suggestions and don’t mind a subscription | NextUpReef |
| You test with a Hanna Marine Master or log from a desktop | Aquarimate |
| You want a private phone log with no account or subscription | Fish Tank Tracker |
| You own an Apex and test only the basics | Apex Fusion |
| You track many elements from ICP tests | A spreadsheet, alongside any app |
If you keep freshwater tanks too, our best freshwater aquarium apps guide covers the apps that handle those better. And if you’re moving off Aquarimate specifically, see Aquarimate alternatives.
How do you get useful data from any reef app? #
The app matters less than the habits behind it. A few rules make trend lines trustworthy:
- Test at the same time of day. pH rises during the light period and falls at night, and alkalinity often dips while the lights are on and corals are calcifying.
- Note the kit. Switching from a Salifert kit to a Hanna checker can shift alkalinity readings by a few tenths of a dKH.
- Log every dose and water change. A calcium jump the day after a 20% water change is expected, not a mystery.
- Retest before you correct. One odd reading is often a testing error. Two in a row is a trend.
- Watch the slope, not the dot. A slow drift of 0.2 dKH a day tells you your dosing needs adjusting before corals react.
Frequently asked questions #
What is the best free reef tank app? #
NextUpReef’s free core and Fish Tank Tracker’s free tier both cover the main reef parameters with charts and reminders. NextUpReef’s free plan is account-based and limited to one tank without Pro. Fish Tank Tracker’s is limited to one tank and a month of history, and needs no account.
Can reef apps import data from a Neptune Apex? #
Some can. Reef Trak imports read-only from Apex Fusion, NextUpReef offers Apex integration in its Pro plan, and Aquarimate supports Apex and Trident controllers. Fish Tank Tracker has no controller imports.
Do reef tank apps need an internet connection? #
Account-based apps need a connection to sign in and sync, though some cache data offline. Fish Tank Tracker and the standard Aquarimate app store data on the device and work without a connection.
Is a reef score or stability score useful? #
It’s a handy summary of how consistently you test and how steady your numbers are. It can’t see coral color, pests or flow problems, so use it as a prompt to look closer, not as a grade for your tank.
Should I log ICP results in an app? #
If you run ICP tests, log them somewhere you can compare over time. Reef Trak supports ICP results. Otherwise a spreadsheet works well, since ICP reports list far more elements than most apps have fields for.