# HYDROS App vs AquariumNotes

The clearest difference is in-app purchases: HYDROS App at none against AquariumNotes's 3. HYDROS App also leads on ads (none vs shown) and iOS requirement (15.6 vs 17.0). AquariumNotes's advantage is update cadence (monthly vs every 3 months). On price and device support there is nothing between them.

Both are free to download. AquariumNotes sells 3 in-app purchases, starting at $2.99 per month. HYDROS App asks for nothing beyond the download.

HYDROS App ships an update every 3 months, AquariumNotes monthly. Both last shipped on October 9, 2026.

## The numbers

| Metric | HYDROS App | AquariumNotes |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.7 (22 ratings)](https://appshunter.io/ios/app/hydros-app/id1455344294/reviews)** | — |
| Number of ratings | **22** | — |
| Positive reviews | 62.3% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 3 months | **Monthly** |
| Monetization | Free | — |
| Size | 70 MB | 7 MB |
| Requires iOS | **15.6** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Coralvue](https://appshunter.io/developer/1455344293) | [Yusuke Morimoto](https://appshunter.io/developer/1702989537) |

## What reviewers say

### HYDROS App

[App page](https://appshunter.io/ios/app/hydros-app/id1455344294)

Easily monitor and control your aquarium's vital parameters like temperature, pH, and salinity. Manage all your connected devices, including ATOs, lights, and pumps, with a user-friendly interface. Quick setup with preset configurations means no coding is required to get your system running.

**Highlights:** Monitor temperature, ORP, pH, salinity, Control ATO, lights, heaters, pumps, User-friendly interface, Quick setup with presets, Manage multiple devices and aquariums, Set schedules and create modes

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

**In-app purchases:** none


### AquariumNotes

[App page](https://appshunter.io/ios/app/aquariumnotes/id6480376453)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| PremiumMember/1Month | $2.99 | per month |
| PremiumMember/6Month | $9.99 | per 6 months |
| PremiumMember/1Year | $19.99 | per year |


## Frequently asked questions

### Is HYDROS App free?

HYDROS App is free to download, with no in-app purchases.

### Is AquariumNotes free?

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

### Do HYDROS App or AquariumNotes have ads?

AquariumNotes shows ads; HYDROS App does not.

### Which is updated more often, HYDROS App or AquariumNotes?

HYDROS App ships an update every 3 months, and AquariumNotes monthly. Most recently, HYDROS App was updated on October 9, 2026 and AquariumNotes on October 9, 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.*