# Aquarium water test log apps for iPhone: 8 compared

> Eight iPhone apps for logging aquarium water tests compared: freshwater or reef, test strip scanning, species database, account, and what each costs.

- Author: [Ivan Chernoknizhnikov](https://treamz.me/), Flutter & iOS Engineer
- Published: 2026-11-11
- URL: https://treamz.me/blog/aquarium-log-apps-compared
- Tags: Aquarium, Fishkeeping, Water Testing, iOS, App Comparison

If you want an iPhone app to log your aquarium water tests, the right one
depends on what else you want from it. For a plain, free log of every tank:
Aquarium - Log Tracker, which I built, so weigh that. For a reef with a
controller: AquaticLog. For a species library with compatibility checks:
Aquarimate or Pocket Marine. To read test strips with the camera: AquaLens. To
know where a new tank is in its cycle: Nitrify. Each section below says where
an app is the better pick, mine included.

The short version:

- **Free, every tank, no account:** Aquarium - Log Tracker.
- **Reef with an Apex, Hydros or Seneye:** AquaticLog.
- **Species library and compatibility, pay once:** Aquarimate ($9.99) or, for
  marine, Pocket Marine ($3.99).
- **Scan test strips, identify fish from a photo:** AquaLens.
- **Cycling a new freshwater tank:** Nitrify.
- **Fish plus reptiles or other pets:** Fishi.
- **Reef with an AI assistant:** Reef Buddy.

## How the eight apps compare

| App | Tanks | Camera reads tests | Species library | Account needed | Price (US) |
|---|---|---|---|---|---|
| [Aquarium - Log Tracker](https://apps.apple.com/us/app/aquarium-log-tracker/id6804384133) | Fresh and salt, unlimited | No | No | No (optional sync) | Free, no in-app purchases |
| [AquaticLog](https://apps.apple.com/us/app/aquaticlog/id583895470) | Fresh and reef, several | No; reads controllers | Livestock records | Yes | Free download |
| [Aquarimate](https://apps.apple.com/us/app/aquarimate/id587215055) | Fresh and salt, unlimited | No | Yes, with compatibility | No (optional cloud) | $9.99 once |
| [Pocket Marine](https://apps.apple.com/us/app/pocket-marine/id999538938) | Saltwater | No | 800+ marine species | No | $3.99 once |
| [Fishi](https://apps.apple.com/us/app/fishi-aquarium-manager/id6450653339) | Fish and other pets | No | Hundreds of species | Not stated | Free download; subscription |
| [Nitrify](https://apps.apple.com/us/app/nitrify-aquarium-water-test/id6787839482) | Freshwater; 1 tank free | No | No | No (iCloud) | Free; Pro is a one-time unlock |
| [AquaLens](https://apps.apple.com/us/app/aqualens-aquarium-log-tracker/id6760222697) | Fresh and salt | Yes, strips and liquid kits | Photo ID | Not stated | Free to start; Pro |
| [Reef Buddy](https://apps.apple.com/us/app/reef-buddy-reef-tank-tracker/id1593580822) | Reef | No | No | Syncs across devices | Free; premium AI |

Everything here is from each app's App Store listing in November 2026. "Not
stated" means the listing doesn't say.

## What makes a water test log worth keeping

A single test says where the tank is today. A log says which way it's going:
nitrate climbing between water changes, alkalinity swinging, a heater that
sticks. Three details decide whether an app's log is trustworthy.

1. **A blank stays blank.** "I didn't test nitrite" and "nitrite was zero" are
   different facts. An app that stores the first as the second draws trends
   that never happened.
2. **Units follow your kit.** Nitrate as NO3 or NO3-N, alkalinity as dKH,
   meq/L or ppm. Mixing them makes a chart lie by a factor of four or more.
3. **Free ammonia, not just total.** Most kits read total ammonia, but the
   toxic part is un-ionised ammonia (NH3), and its share grows with pH and
   temperature: [roughly ten times larger at pH 8 than at pH 7](https://www.epa.gov/caddis/ammonia).

Then there's what you want beyond the log: reminders, a species library,
camera scanning, controller data, or help while a new tank cycles.

## Aquarium - Log Tracker: a free log for every tank

[Aquarium - Log Tracker](https://apps.apple.com/us/app/aquarium-log-tracker/id6804384133)
puts every parameter a tank tracks on one page, with your last values in grey,
and a timer per test for the wait between reagent and reading. A field you
leave blank is never stored as zero. After you save, it works out free ammonia
from the pH and temperature in the same session and flags readings outside the
tank's target band.

All parameters share one time axis on the charts, so a temperature spike and a
nitrate spike line up, and livestock losses are marked across all of them.
There are reminders for water changes, testing, filters and dosing across
every tank, a livestock and equipment list, and a journal. While a tank
cycles, it shows which stage the readings point to and calls it cycled only
after two sessions in a row with ammonia and nitrite clear and nitrate
present.

It's free with no in-app purchases, subscription or ads, for as many tanks as
you keep. Signed out, everything stays on the phone; sign in only if you want
it on another device. Export to CSV and JSON is free.

**Limits:** iPhone only (iOS 13 or later), English only, every value typed by
hand (no strip scanning, no controllers), no species database, and no import
of old logs beyond backdating readings one at a time.

![Aquarium's log screen: one page of fields, previous values in grey, a timer beside each](https://treamz.me/blog/aquarium-water-test-log-app/quick-log.jpg "Aquarium - Log Tracker: blank fields are not recorded as zero")

## AquaticLog: account-based, with controller data

[AquaticLog](https://apps.apple.com/us/app/aquaticlog/id583895470) has been
around since 2013 and rates 4.2 from 409 ratings. Your log lives in an
AquaticLog account, so it's on your iPhone, iPad and the web at
aquaticlog.com. It logs the usual parameters and can pull hourly readings from
a Neptune Apex, Hydros, AquaWiz or Seneye, including Seneye's NH3 and NH4. It
keeps detailed livestock records with reef-safety and temperament, schedules
retests for out-of-range results, and has Home Screen widgets.

**Pick it if** you run a reef or a high-tech tank with a controller, or want
your log in a browser too. It needs iOS 18.1 or later and an account.

## Aquarimate: species library and compatibility

[Aquarimate](https://apps.apple.com/us/app/aquarimate/id587215055) costs
$9.99 once and rates 4.4 from 626 ratings. It manages unlimited fresh and
saltwater tanks, lets you add or remove parameters per tank, has unit
converters and dosing calculators, a test timer, and charts that plot several
parameters with your maintenance on one graph. Its Aquaribase library covers
fish, coral, invertebrates and plants with compatibility advice, and it tracks
expenses and equipment. It's available in 13 languages; the last update was in
June 2025.

**Pick it if** you want a stocking library and compatibility checks in the
same app as your log, and prefer to pay once.

## Pocket Marine: for saltwater keepers

[Pocket Marine](https://apps.apple.com/us/app/pocket-marine/id999538938)
costs $3.99 once and has the best rating here, 4.8 from 597 ratings. It's
built for marine tanks: an encyclopaedia of over 800 marine fish,
invertebrates and corals with compatibility notes, a testing journal for more
than 30 parameters with trend graphs, dosing and water change logs, an
inhabitants diary and reminders. It was last updated in April 2024.

**Pick it if** you keep a saltwater tank and want a species reference
alongside the log for a small one-off price.

## Fishi: fish and every other pet

[Fishi](https://apps.apple.com/us/app/fishi-aquarium-manager/id6450653339)
rates 4.6 from 596 ratings and covers terrariums, aviaries and enclosures as
well as aquariums. It monitors water parameters, gives insights on cycling
progress, has feeding and maintenance reminders, and a library of hundreds of
fish, reptile, insect, bird and small animal species. It runs on a monthly,
quarterly or yearly subscription.

**Pick it if** you keep reptiles or other animals as well as fish and want
them in one app.

## Nitrify: for a tank that's still cycling

[Nitrify](https://apps.apple.com/us/app/nitrify-aquarium-water-test/id6787839482)
is for freshwater keepers. You log ammonia, nitrite and nitrate, and it puts
every test in a cycle stage (waiting on ammonia, the nitrite spike, finishing,
cycled) with a Safe, Watch or Act call on each reading. The free version
covers logging, the cycle stage, the safety verdict, one tank and iCloud sync;
a one-time Pro unlock adds multiple tanks, reminders, custom schedules and an
estimate of when the cycle will finish. Nothing is sent to a server. It needs iOS 26.2 or later.

**Pick it if** you're cycling your first freshwater tank and want a plain
verdict on every reading.

## AquaLens: camera scanning and photo ID

[AquaLens](https://apps.apple.com/us/app/aqualens-aquarium-log-tracker/id6760222697)
scans test strips and liquid test kit results with the camera, identifies
fish, plants, corals, algae and snails from a photo, and gives AI guidance
based on your tank history. It also keeps the usual log, chemistry trends and
maintenance timeline. It's free to start, with a Pro tier for advanced
analysis, and rates 4.6 from 32 ratings.

**Pick it if** typing readings is what stops you logging, or you want to
identify what's in your tank.

## Reef Buddy: reef tracking with an AI assistant

[Reef Buddy](https://apps.apple.com/us/app/reef-buddy-reef-tank-tracker/id1593580822)
logs reef parameters (KH, salinity, pH, calcium, magnesium, nitrate,
phosphate, silicate and more) with trends and automated insights, and syncs
between iPhone and iPad. A premium tier adds Shrimpy, an assistant that
analyses your data and tank photos and answers questions. It needs iOS 26 or
later and rates 3.9 from 20 ratings.

**Pick it if** you keep a reef and want to ask questions about your numbers.

## Which aquarium log app should you use?

- **You want a free, honest log for one or many tanks:** Aquarium - Log
  Tracker.
- **You have a controller or want a web log:** AquaticLog.
- **You want a species library and pay once:** Aquarimate, or Pocket Marine
  for saltwater.
- **You won't type readings:** AquaLens.
- **Your first freshwater tank is cycling:** Nitrify.
- **You keep more than fish:** Fishi.

## FAQ

### What is the best app to log aquarium water tests?

It depends on the tank. Aquarium - Log Tracker is free with no in-app purchases
for any number of fresh or saltwater tanks; AquaticLog adds controller data and
a web log; Aquarimate and Pocket Marine add species libraries for a one-off
price; AquaLens reads test strips with the camera.

### Is there a free aquarium log app with no subscription?

Yes. Aquarium - Log Tracker is free with no in-app purchases, subscription or
ads, for unlimited tanks, and exports to CSV and JSON for free. Nitrify's free
version covers one freshwater tank, with a one-time Pro unlock for more.

### Which aquarium app can read test strips with the camera?

AquaLens scans test strips and liquid test kit results with the iPhone camera
and keeps the readings in its log. Most other aquarium log apps, including
Aquarium - Log Tracker, need readings typed in.

### Which app tracks the nitrogen cycle in a new tank?

Nitrify puts every freshwater test into a cycle stage with a Safe, Watch or Act
verdict. Aquarium - Log Tracker shows which stage the readings point to and
calls a tank cycled after two sessions in a row with ammonia and nitrite clear
and nitrate present.

### Is there a reef tank app that connects to a Neptune Apex?

AquaticLog can pull hourly readings from a Neptune Apex, Hydros, AquaWiz or
Seneye into its log, alongside manual tests.

### Can I track several aquariums in one app?

Yes. Aquarium - Log Tracker and Aquarimate handle unlimited tanks; Aquarium -
Log Tracker charges nothing for extra ones, and Aquarimate is a one-off $9.99.
Nitrify and others limit the free version to one tank.

### Is Aquarium - Log Tracker free?

Yes. It's free to download, with no in-app purchases, subscription or ads, and
no account is needed. It's iPhone only and needs iOS 13 or later.