Comparison

BiAffect3 vs Hydro Hero

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

BiAffect3

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
Read full description

BiAffect3 is the new and improved version of our award-winning BiAffect app, part of a multi-year mood-tracking research project developed by researchers at the University of Illinois at Chicago and funded by the National Institute of Mental Health. BiAffect3 • Track your mood and neurocognitive functioning with your iPhone. • Use keystroke dynamics and sensor data to gain insights into your mental health. • Help researchers develop new tools to improve the diagnosis and treatment of mood disorders. How does it work? BiAffect3 uses a custom-built virtual smartphone keyboard to collect keystroke metadata—such as typing speed, errors, and pauses—but not typed content in order to preserve user privacy. This data is then analyzed using machine learning algorithms and other statistical techniques to identify patterns that are associated with different mood states. Who is BiAffect3 for? BiAffect3 is for anyone who is interested in tracking their mood and neurocognitive functioning. The app is particularly useful for people with mood disorders as it can help them to identify early warning signs of an episode and take steps to prevent it, but it can be used by anyone who wants to learn more about their individual emotional and thought patterns. How do I get started? To get started with BiAffect3, simply download the app and create an account. The app will then guide you through the setup process. How can I help? By participating in the BiAffect3 study, you can help researchers develop new tools to improve the diagnosis and treatment of bipolar disorder. Your participation is voluntary and confidential. Download BiAffect3 today and start tracking your mood and neurocognitive functioning.

About

Hydro Hero

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
Read full description

Staying hydrated has never been this fun. Hydro Hero turns every glass of water into a rewarding daily challenge — log your drinks, watch your tank fill up, and celebrate the moment you reach your daily hydration goal. WHY YOU'LL LOVE HYDRO HERO Satisfying Drink Logging Every drink fills your tank with a fun, animated reveal. Log your intake, watch your progress rise, and celebrate when you hit your goal. Sound Packs Make hydration genuinely satisfying with upgraded sound effects and haptics as you log — or record your own custom sounds to play each time you drink (PRO). Streaks & Achievements Build daily streaks and unlock 20+ badges as you stay consistent — from First Drop to Perfect Week. Stats & Trends Track your weekly summary, beverage breakdown, and progress charts at a glance. Track Any Drink Water, coffee, tea, soda, juice, sports drinks and more — each with smart hydration efficiency. Add custom amounts in oz or ml. Hydrate With Your Squad Add friends, share your progress, and cheer each other on to stay motivated together. Apple Health Sync: Read and write your water intake to Apple Health, keeping your hydration alongside the rest of your health data. Reminders & Widgets: Get gentle nudges to drink up, and check your progress right from your Home Screen. On Your Apple Watch Log any drink straight from your wrist — pick a beverage, tap a preset or dial in a custom amount with the Digital Crown, and see your progress, goal, and streak sync instantly with your iPhone. Siri on iPhone and Apple Watch — "Hey Siri, log preset [name] in Hydro Hero" — log any of your saved presets from your Phone or Watch, hands-free. Hero Missions: Turn your daily goal into a quest. Four evergreen Mission chains — The Hero's Journey, Tea Time, Hourly Hydration, and Dry Spell — let you earn Hero Sigils, miss-day Shields, and unlock new powers as you complete Bronze, Silver, and Gold tiers. Live Activity: Keep your tank on your Lock Screen and Dynamic Island so you can check your hydration at a glance. Opt in anytime — off by default. Family Mode: One phone, the whole household. Each family member gets their own profile with their own goal, streak, history, and emoji avatar — and you can see everyone's progress on the Squad tab. Free for 2 profiles, Pro unlocks up to 5. Everything stays local — no cloud, no accounts. Make every sip count. Download Hydro Hero and make hydration the best part of your day! ———————— Hydro Hero PRO is available as an auto-renewing monthly subscription or a one-time lifetime purchase. • Payment is charged to your Apple ID account at confirmation of purchase. • Your subscription automatically renews unless auto-renew is turned off at least 24 hours before the end of the current period. • Your account is charged for renewal within 24 hours prior to the end of the current period, at the price shown in the app. • You can manage or cancel your subscription in your App Store account settings after purchase. Privacy Policy: https://wimsby.github.io/Hydro-Hero/privacy-policy.html Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

BiAffect33 screens
Hydro Hero4 screens

Verdict

The call

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.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

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.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard4 real differences · 6 level
BiAffect3 versus Hydro Hero: the parameters behind the verdict, then further details
ParameterBiAffect3Hydro Hero
PriceFreeFree
Rating4.9 (7 ratings)5.0 (7 ratings) — better
Positive reviews—100.0% of reviews
Number of ratings77
Update frequencyEvery 4 monthsEvery 4 days — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFreemium
DevicesiPhoneiPhone, iPad, iPod, Apple Watch — better
Requires iOS16.115.1 — better
Further details — not scored
Size30 MB67 MB
Age rating17+12+
DeveloperUniversity of IllinoisDylan Matuschka

Customer experience

BiAffect3

All ratings4 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

Hydro Hero

All ratings7 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

BiAffect3

No in-app purchases

2 purchases

Hydro Hero

Subscriptions1
  • Pro Access - Monthly$0.991 Month
One-time1
  • Pro Access - One Time$9.99

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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