# Acid Base pH vs Chess Opener PRO

The clearest difference is rating: Acid Base pH at 5.0 against Chess Opener PRO's 4.4. Acid Base pH also leads on review sentiment (100% vs 76%) and price ($3.99 vs $8.99). Chess Opener PRO's advantage is ratings volume (79 vs 1) and update cadence (every 5 weeks vs every 3 months). On ads, in-app purchases, monetization model and device support there is nothing between them.

Acid Base pH costs $3.99 and Chess Opener PRO $8.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Acid Base pH holds the better App Store score, 5.0 against 4.4. That said, the two scores are not equally well evidenced: Chess Opener PRO has 79 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 100% of Acid Base pH's written reviews are positive against 76% of Chess Opener PRO's.

Acid Base pH ships an update every 3 months, Chess Opener PRO every 5 weeks. The most recent releases landed on November 6, 2026 and November 7, 2026 respectively.

## The numbers

| Metric | Acid Base pH | Chess Opener PRO |
| --- | --- | --- |
| Price | **$3.99** | $8.99 |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/acid-base-ph/id977951851/reviews)** | [4.4 (79 ratings)](https://appshunter.io/ios/app/chess-opener-pro/id1489282483/reviews) |
| Number of ratings | 1 | **79** |
| Positive reviews | **100.0% of reviews** | 75.9% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 5 weeks** |
| Monetization | Paid | Paid |
| Size | 2 MB | 149 MB |
| Requires iOS | 17.1 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Roman Volinsky](https://appshunter.io/developer/977951850) | [Stanislav Basovnik](https://appshunter.io/developer/1469334974) |

## What reviewers say

### Acid Base pH

[App page](https://appshunter.io/ios/app/acid-base-ph/id977951851)

Accurately estimate pH values for acid-base aqueous systems. Calculate pH for weak and strong acids/bases, plot titration curves, and find equivalent points. Export data and find titrant volumes for desired pH.

**Highlights:** Estimate pH of acid-base solutions, Plot titration curves, Find pH and titrant volume at equivalent points, Export titration plots as image or data, Calculate titrant volume for desired pH, Includes list of common indicators

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

**In-app purchases:** none


### Chess Opener PRO

[App page](https://appshunter.io/ios/app/chess-opener-pro/id1489282483)

Master chess openings with a comprehensive trainer and explorer. Analyze grandmaster repertoires, build your own opening lines, and memorize variations with interactive training. Works offline with no ads.

**Highlights:** Chess opening tree with statistics, Encyclopedia of Chess Openings (ECO), Grandmaster repertoire database, Stockfish engine analysis, Interactive opening trainer, Build and manage opening repertoire, PGN import/export

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

**In-app purchases:** none

**What reviewers like**

- 👍 Excellent for learning openings
- 🚀 Fast and responsive
- 💡 Highly customizable repertoires
- 👍 Intuitive and easy to use
- 👍 Great for serious players

**What reviewers complain about**

- 🐛 Crashes quite often
- 🐛 Not intuitive to use
- 🐛 Invalid PGN import
- 🐛 Does not train beyond opening position
- 🐛 Repeats same variation

**Reported bugs**

- Invalid PGN import
- Crashes quite often
- Repeats same variation
- Cannot review lines while training
- App not functioning with iOS 16.7.4

**Requested features**

- Include position setting
- Start study from a later position
- Multiple folders for simultaneous practice
- Option to switch between figure visibility modes (normal, queen pieces, none)
- Blindfold practice option


## Frequently asked questions

### Is Acid Base pH free?

Acid Base pH costs $3.99, with no in-app purchases.

### Is Chess Opener PRO free?

Chess Opener PRO costs $8.99, with no in-app purchases.

### Which has better reviews, Acid Base pH or Chess Opener PRO?

Acid Base pH is rated higher. Acid Base pH averages 5.0 out of 5 from 1 ratings, while Chess Opener PRO averages 4.4 from 79 ratings.

### Do Acid Base pH or Chess Opener PRO have ads?

Neither Acid Base pH nor Chess Opener PRO shows ads.

### Which is updated more often, Acid Base pH or Chess Opener PRO?

Acid Base pH ships an update every 3 months, and Chess Opener PRO every 5 weeks. Most recently, Acid Base pH was updated on November 6, 2026 and Chess Opener PRO on November 7, 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.*