# BiAffect3 vs Hydro Hero

The clearest difference is in-app purchases: BiAffect3 at none against Hydro Hero's 2. Hydro Hero's advantage is update cadence (every 4 days vs every 4 months) and device support (4 vs 1). On price, rating, ratings volume and ads there is nothing between them.

Both are free to download. Hydro Hero sells 2 in-app purchases, starting at $0.99 per month. BiAffect3 asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 4.9 for BiAffect3 against 5.0 for Hydro Hero. Both are backed by a comparable volume of ratings — 7 and 7 respectively.

BiAffect3 ships an update every 4 months, Hydro Hero every 4 days. The most recent releases landed on October 24, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | BiAffect3 | Hydro Hero |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.9 (7 ratings)](https://appshunter.io/ios/app/biaffect3/id6451423106/reviews) | **[5.0 (7 ratings)](https://appshunter.io/ios/app/hydro-hero/id6764692053/reviews)** |
| Number of ratings | 7 | 7 |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 4 days** |
| Monetization | **Free** | Freemium |
| Size | 30 MB | 67 MB |
| Requires iOS | 16.1 | **15.1** |
| Devices | iPhone | **iPhone, iPad, iPod, Apple Watch** |
| Age rating | 17+ | 12+ |
| Developer | [University of Illinois](https://appshunter.io/developer/422670617) | [Dylan Matuschka](https://appshunter.io/developer/1895881125) |

## What reviewers say

### BiAffect3

[App page](https://appshunter.io/ios/app/biaffect3/id6451423106)

This app helps you track your mood and cognitive function using your iPhone's keyboard and sensor data. It analyzes typing patterns to provide insights into mental health and assists researchers in developing better diagnostic tools for mood disorders.

**Highlights:** Mood tracking, Neurocognitive functioning assessment, Keystroke dynamics analysis, Sensor data collection, Mental health insights, Research participation

**In-app purchases:** none


### Hydro Hero

[App page](https://appshunter.io/ios/app/hydro-hero/id6764692053)

This app makes staying hydrated enjoyable by turning each drink into a rewarding challenge. Log your intake, visualize your progress, and celebrate reaching your daily hydration goals with fun animations and sound effects.

**Highlights:** Log drinks with animated reveals, Customizable sound packs, Streaks and achievement badges, Detailed stats and trends, Track various beverage types, Sync with Apple Health, Reminders and widgets, Apple Watch integration

**Features:** macOS Compatibility, Apple Watch app

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Access - Monthly | $0.99 | per month |
| Pro Access - One Time | $9.99 | one-time |


## Frequently asked questions

### Is BiAffect3 free?

BiAffect3 is free to download, with no in-app purchases.

### Is Hydro Hero free?

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

### Which has better reviews, BiAffect3 or Hydro Hero?

Hydro Hero is rated higher. BiAffect3 averages 4.9 out of 5 from 7 ratings, while Hydro Hero averages 5.0 from 7 ratings.

### Do BiAffect3 or Hydro Hero have ads?

Neither BiAffect3 nor Hydro Hero shows ads.

### Which is updated more often, BiAffect3 or Hydro Hero?

BiAffect3 ships an update every 4 months, and Hydro Hero every 4 days. Most recently, BiAffect3 was updated on October 24, 2026 and Hydro Hero on October 5, 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.*