# HYDROS App vs Reef Stability

The clearest difference is in-app purchases: HYDROS App at none against Reef Stability's 3. HYDROS App also leads on device support (3 vs 1) and iOS requirement (15.6 vs 18.0). Reef Stability's advantage is update cadence (weekly vs every 3 months). On price and ads there is nothing between them.

Both are free to download. Reef Stability sells 3 in-app purchases, starting at $6.99 per month. HYDROS App asks for nothing beyond the download.

HYDROS App ships an update every 3 months, Reef Stability weekly. The most recent releases landed on September 30, 2026 and September 9, 2026 respectively.

## The numbers

| Metric | HYDROS App | Reef Stability |
| --- | --- | --- |
| 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 | No |
| Update frequency | Every 3 months | **Weekly** |
| Monetization | Free | — |
| Size | 70 MB | 9 MB |
| Requires iOS | **15.6** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Coralvue](https://appshunter.io/developer/1455344293) | [YUSUF AYDIN](https://appshunter.io/developer/6771871523) |

## 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


### Reef Stability

[App page](https://appshunter.io/ios/app/reef-stability-dosing-tracker/id6799461220)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium Monthly | $6.99 | per month |
| Premium Annual | $39.99 | per year |
| Premium Lifetime | $89.99 | one-time |


## Frequently asked questions

### Is HYDROS App free?

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

### Is Reef Stability free?

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

### Do HYDROS App or Reef Stability have ads?

Neither HYDROS App nor Reef Stability shows ads.

### Which is updated more often, HYDROS App or Reef Stability?

HYDROS App ships an update every 3 months, and Reef Stability weekly. Most recently, HYDROS App was updated on September 30, 2026 and Reef Stability on September 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.*