# Nitrox Buddy vs Poseidon Reef

The clearest difference is review sentiment: Nitrox Buddy at 96% against Poseidon Reef's 0%. Nitrox Buddy also leads on rating (4.9 vs 3.0) and ads (none vs shown). Poseidon Reef's advantage is in-app purchases (none vs 1) and update cadence (every 5 weeks vs every 7 months). On price and device support there is nothing between them.

Both are free to download. Nitrox Buddy sells 1 one-off in-app purchase. Poseidon Reef asks for nothing beyond the download.

Nitrox Buddy holds the better App Store score, 4.9 against 3.0. That said, the two scores are not equally well evidenced: Nitrox Buddy has 468 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 96% of Nitrox Buddy's written reviews are positive against 0% of Poseidon Reef's.

Nitrox Buddy ships an update every 7 months, Poseidon Reef every 5 weeks. The most recent releases landed on October 14, 2026 and September 30, 2026 respectively.

## The numbers

| Metric | Nitrox Buddy | Poseidon Reef |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.9 (468 ratings)](https://appshunter.io/ios/app/nitrox-buddy/id572411073/reviews)** | [3.0 (2 ratings)](https://appshunter.io/ios/app/poseidon-reef/id1581432645/reviews) |
| Number of ratings | **468** | 2 |
| Positive reviews | **95.7% of reviews** | 0.0% of reviews |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | Every 7 months | **Every 5 weeks** |
| Monetization | Free with in-app purchases | **Ad-supported** |
| Size | 6 MB | 58 MB |
| Requires iOS | 26.0 | **12.1** |
| Devices | iPhone, iPod, Apple Watch | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Gereon Steffens](https://appshunter.io/developer/493030228) | [Poseidon Diving Systems AB](https://appshunter.io/developer/567839779) |

## What reviewers say

### Nitrox Buddy

[App page](https://appshunter.io/ios/app/nitrox-buddy/id572411073)

This application serves as a straightforward calculator for nitrox and enriched air divers. It quickly computes essential dive data such as Maximum Operating Depth (MOD), Equivalent Air Depth (EAD), Best Mix, and Partial Pressure of Oxygen (PPO2). It supports both imperial and metric units and offers a companion watch app for on-the-go calculations.

**Highlights:** Calculate MOD, EAD, Best Mix, PPO2, Imperial and metric unit support, Sea and fresh water options, Selectable max oxygen content, Selectable max partial pressure, Companion watch app

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Tip | $0.99 | one-time |

**What reviewers like**

- 👍 Easy to use
- 🚀 Quick calculations
- ✅ Accurate results
- 💡 Free to use
- 🎯 Essential for Nitrox divers

**What reviewers complain about**

- 📱 Ugly iPad icon
- ⚠️ MOD calculation limited to 40% O2 in older versions
- ⚠️ MOD calculation limited to 50% O2 in older versions
- ⚠️ Needs to work with older iOS versions

**Reported bugs**

- iPad icon is ugly
- MOD limit of 50% O2 despite 100% O2 setting (resolved)
- MOD limit of 40% O2 (older version)
- Does not work with older iOS versions

**Requested features**

- Add MOD 1.5 option
- Allow MOD calculation up to 100% O2 and indicate max exposure duration
- Change color for inappropriate mixes (e.g., 50% at 40m)
- Support older iOS versions (5 & 6)


### Poseidon Reef

[App page](https://appshunter.io/ios/app/poseidon-reef/id1581432645)

This app helps divers log, plan, and analyze their dives. It offers detailed overviews, customizable dive logs, and advanced planning for various dive types. Connect your dive computer to manage data and firmware.

**Highlights:** Comprehensive dive logging, Detailed dive planning, Support for OC and CCR dives, Unlimited tank support, Decompression model selection, Dive computer connectivity, Cloud backup and firmware updates

**In-app purchases:** none


## Frequently asked questions

### Is Nitrox Buddy free?

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

### Is Poseidon Reef free?

Poseidon Reef is free to download, with no in-app purchases.

### Which has better reviews, Nitrox Buddy or Poseidon Reef?

Nitrox Buddy is rated higher. Nitrox Buddy averages 4.9 out of 5 from 468 ratings, while Poseidon Reef averages 3.0 from 2 ratings.

### Do Nitrox Buddy or Poseidon Reef have ads?

Poseidon Reef shows ads; Nitrox Buddy does not.

### Which is updated more often, Nitrox Buddy or Poseidon Reef?

Nitrox Buddy ships an update every 7 months, and Poseidon Reef every 5 weeks. Most recently, Nitrox Buddy was updated on October 14, 2026 and Poseidon Reef on September 30, 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.*