# TankDiary vs Aquarium Harmony

The clearest difference is ads: TankDiary at none against Aquarium Harmony's shown. TankDiary also leads on update cadence (every 11 days vs every 6 weeks). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Both are free to download. TankDiary sells 2 in-app purchases, starting at $9.99 per year and Aquarium Harmony sells 3 in-app purchases, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.

TankDiary ships an update every 11 days, Aquarium Harmony every 6 weeks. Both last shipped on October 24, 2026.

## The numbers

| Metric | TankDiary | Aquarium Harmony |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (2 ratings)](https://appshunter.io/ios/app/tankdiary-aquarium-tracker/id6788005172/reviews)** | — |
| Number of ratings | **2** | — |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 11 days** | Every 6 weeks |
| Monetization | Free with in-app purchases | — |
| Size | 2 MB | 15 MB |
| Requires iOS | **17.0** | 18.0 |
| Devices | iPhone | **iPhone, Apple Watch** |
| Age rating | 4+ | 4+ |
| Developer | [TOBY M BERGER](https://appshunter.io/developer/6776950197) | [Georgiy Gorokhov](https://appshunter.io/developer/1806278466) |

## What reviewers say

### TankDiary

[App page](https://appshunter.io/ios/app/tankdiary-aquarium-tracker/id6788005172)

Easily track aquarium water parameters, schedule maintenance, and monitor your tank's health. This app helps you understand your tank's cycling stage and provides reliable reminders for water changes and other tasks. It offers detailed logging and historical charts for long-term trend analysis.

**Highlights:** Log water test results (ammonia, nitrite, nitrate, pH, etc.), Identify aquarium cycle stage, Schedule maintenance reminders (water changes, dosing), Water change calculator, Livestock and photo journal, Offline functionality, Interactive historical charts

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| TankDiary Pro — Yearly | $9.99 | per year |
| TankDiary Pro — Lifetime | $24.99 | one-time |


### Aquarium Harmony

[App page](https://appshunter.io/ios/app/aquarium-harmony/id6790428231)

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium — Monthly | $4.99 | per month |
| Premium — Annual | $19.99 | per year |
| Premium — Lifetime | $39.99 | one-time |


## Frequently asked questions

### Is TankDiary free?

TankDiary is free to download, with in-app purchases available.

### Is Aquarium Harmony free?

Aquarium Harmony is free to download, with in-app purchases available.

### Do TankDiary or Aquarium Harmony have ads?

Aquarium Harmony shows ads; TankDiary does not.

### Which is updated more often, TankDiary or Aquarium Harmony?

TankDiary ships an update every 11 days, and Aquarium Harmony every 6 weeks. Most recently, TankDiary was updated on October 24, 2026 and Aquarium Harmony on October 24, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*