# LSI Pool and Spa Calculator vs MathRoomBuddy

The clearest difference is price: LSI Pool and Spa Calculator at Free against MathRoomBuddy's $0.99. LSI Pool and Spa Calculator also leads on update cadence (every 6 weeks vs every 22 months). MathRoomBuddy's advantage is in-app purchases (none vs 2) and iOS requirement (12.0 vs 17.6). On rating, ratings volume, ads and monetization model there is nothing between them.

LSI Pool and Spa Calculator is free to download; MathRoomBuddy costs $0.99 up front. LSI Pool and Spa Calculator sells 2 in-app purchases, starting at $1.99 per month. MathRoomBuddy asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 5.0 for LSI Pool and Spa Calculator against 5.0 for MathRoomBuddy. Both are backed by a comparable volume of ratings — 1 and 2 respectively.

LSI Pool and Spa Calculator ships an update every 6 weeks, MathRoomBuddy every 22 months. The most recent releases landed on October 23, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | LSI Pool and Spa Calculator | MathRoomBuddy |
| --- | --- | --- |
| Price | **Free** | $0.99 |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/lsi-pool-and-spa-calculator/id373769371/reviews) | [5.0 (2 ratings)](https://appshunter.io/ios/app/mathroombuddy/id1466211804/reviews) |
| Number of ratings | 1 | **2** |
| Positive reviews | 75.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 6 weeks** | Every 22 months |
| Monetization | Paid | Paid |
| Size | 7 MB | 8 MB |
| Requires iOS | 17.6 | **12.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Verosocial Studio](https://appshunter.io/developer/354566841) | [Mike Green](https://appshunter.io/developer/1466211803) |

## What reviewers say

### LSI Pool and Spa Calculator

[App page](https://appshunter.io/ios/app/lsi-pool-and-spa-calculator/id373769371)

Easily calculate and track the Langelier Saturation Index for your pool water. Maintain optimal water balance for a healthy and safe swimming environment. Supports multiple units and saves your calculations over time.

**Highlights:** LSI Calculation, Water Chemistry Tracking, Email Calculations, CSV Export, Offline Use, Universal App Support

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| LSI Calculators pro Monthly | $1.99 | per month |
| LSI Calculators pro lifetime | $14.99 | one-time |


### MathRoomBuddy

[App page](https://appshunter.io/ios/app/mathroombuddy/id1466211804)

This utility app converts between IEEE floating-point and raw values, as well as hexadecimal and decimal formats. It also functions as a simple RPN calculator.

**Highlights:** IEEE floating-point conversion, Hexadecimal to decimal conversion, Decimal to hexadecimal conversion, RPN calculator functionality

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is LSI Pool and Spa Calculator free?

LSI Pool and Spa Calculator is free to download, with in-app purchases available.

### Is MathRoomBuddy free?

MathRoomBuddy costs $0.99, with no in-app purchases.

### Which has better reviews, LSI Pool and Spa Calculator or MathRoomBuddy?

LSI Pool and Spa Calculator and MathRoomBuddy are both rated 5.0 out of 5 on the App Store, from 1 and 2 ratings respectively.

### Do LSI Pool and Spa Calculator or MathRoomBuddy have ads?

Neither LSI Pool and Spa Calculator nor MathRoomBuddy shows ads.

### Which is updated more often, LSI Pool and Spa Calculator or MathRoomBuddy?

LSI Pool and Spa Calculator ships an update every 6 weeks, and MathRoomBuddy every 22 months. Most recently, LSI Pool and Spa Calculator was updated on October 23, 2026 and MathRoomBuddy on October 20, 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.*