# LSI Pool and Spa Calculator — Water Balance and Service Log

> Pool water chemistry calculator for Langelier Saturation Index. (iPhone/iPad app by Verosocial Studio.)

- Source: https://appshunter.io/ios/app/lsi-pool-and-spa-calculator/id373769371 (this page in markdown: same URL + `.md`)
- Developer: [Verosocial Studio](https://appshunter.io/developer/354566841)
- Category: Utilities, Business
- Price: Free with in-app purchases
- Rating: 5.00/5 from 1 App Store ratings · 12 written reviews indexed
- Age rating: 4+
- Requires: iOS 17.6 · 7 MB
- Languages: American English
- Released: 2010-05-27
- Data updated: 2026-10-23
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/lsi-pool-and-spa-calculator/id373769371/reviews.md

## What is LSI Pool and Spa Calculator?

You take pride in caring for pools and spas, and your attention to each reading matters. Thank you for using LSI Pool and Spa Calculator to keep water balance checks, customer details, and service records together.

Maintain a pool route, look after a commercial property, or care for your own spa with a water chemistry app that calculates the Langelier Saturation Index and keeps your visit history. Check a result, save the visit, and review the details before your next test.

CHECK WATER BALANCE

- Calculate LSI using pH, water temperature, calcium hardness, total alkalinity, and total dissolved solids.
- See LSI, predicted saturation pH, and a result category.
- Review whether your readings indicate a tendency toward scale or corrosion.
- Enter temperature in Fahrenheit or Celsius.
- Switch units with automatic temperature conversion.
- Use the built-in guide to understand the calculation and its inputs.

KEEP A SERVICE HISTORY

- Save readings under reusable pool, spa, or property names.
- Add visit dates and notes about treatments, observations, or follow-up work.
- Search records by site, date, notes, or result category.
- Sort history to find recent visits or review earlier readings.
- Edit saved measurements and recalculate after a correction.
- Duplicate a previous record for repeat visits.
- Review the selected reading beside your records list on iPad.

ORGANIZE CUSTOMERS AND PROPERTIES

- Store customer names, companies, phone numbers, email addresses, and notes.
- Add contacts manually or choose people to import from device Contacts.
- Link several properties to one customer.
- Keep a separate address and notes for each site.
- Search customer details when you need a phone number or service context.
- Edit local customer copies without changing device Contacts.
- Keep sites and readings when you remove a customer.

FIND SITES ON THE MAP

- Open Site Map from Stats to see properties with resolved addresses.
- Use the site's address or its linked customer's address.
- Tap a pin to open customer details and linked sites.
- Find all saved sites in the searchable list, including those awaiting an address.
- Add or correct an address and retry its lookup.

REVIEW YOUR WATER CHEMISTRY

- Compare minimum, maximum, and average readings by site.
- View charts for LSI, pH, temperature, calcium hardness, alkalinity, and TDS.
- Filter saved readings by result category.
- Open a complete reading from Stats when you need the details.
- Use sortable spreadsheet review to compare service history.

MAKE QUICK CHECKS BETWEEN VISITS

- Use Quick Calc without adding a reading to site history.
- Keep recent calculator inputs and the latest result on this device.
- Reuse values when testing similar water.
- Reset the calculator for a fresh check.

REPORTS AND BACKUPS

- Share a calculation as text or a PDF report.
- Export readings, sites, or contacts as CSV files for spreadsheets.
- Create PDF reports for your chosen information.
- Save a readings backup or a complete backup with customers and site links.
- Import a JSON backup while skipping exact duplicates.
- Share files through the iPhone and iPad share sheet.

Choose Light, Dark, or system appearance and set your preferred temperature units. Habits & Progress lets you set testing goals and review milestones inside the app.

Start with up to five saved records in the free version. LSI Pro unlocks a larger record allowance, spreadsheet review, backup import, individual report sharing, and printing. Monthly and lifetime purchase options are available.

Use LSI alongside reliable water tests and equipment guidance. Keep measurements, property details, and notes ready for your next service day.

Monthly Pro is a 1-month auto-renewable subscription.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

## Key features

- LSI Calculation
- Water Chemistry Tracking
- Email Calculations
- CSV Export
- Offline Use
- Universal App Support

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| LSI Calculators pro Monthly | $1.99 | per month |

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| LSI Calculators pro lifetime | $14.99 | one-time |


## Is LSI Pool and Spa Calculator safe?

Not enough ratings yet to assess LSI Pool and Spa Calculator.

## Is LSI Pool and Spa Calculator legit?

LSI Pool and Spa Calculator appears to be a legitimate app. The AppsHunter Legitimacy Score for LSI Pool and Spa Calculator is 90 out of 100 points across 7 verification signals from App Store and developer data.

## Recent user reviews (10 of 12)

All indexed reviews: https://appshunter.io/ios/app/lsi-pool-and-spa-calculator/id373769371/reviews.md

### 5/5 — Really great app that keeps setting feature features

*2026-10-07*

The new contacts feature is incredible because I can finally organize the pools and spas and what not

### 5/5 — Works great for tracking

*2026-09-10*

The graphing and charting is particularly useful and a great addition to

### 1/5 — One off fee payment removed

*2026-06-25*

Paid the one off fee to use the app, accessed a few week, but has now stopped working and ‘restoring’ the purchase does not work either. So can no longer use.

### 5/5 — Works great

*2026-05-28*

Very pleased with the direction it’s going especially the spreadsheet view so I can look at a lot of records and data at the same time

### 5/5 — Handy for work and testing

*2017-06-09*

Good to have available for record keeping...

New database functionality is very nice, especially with the auto save.

Exporting to spreadsheets format is very helpful.

Sync works great over iCloud

### 3/5 — Handy, but needs expansion to include sulfate

*2015-05-27*

Not bad

### 5/5 — Great app

*2013-08-12*

Very useful app.

### 5/5 — Best app for LSI

*2013-06-19*

Would like to see a history of values and graph trends with a place for comments about what actions were taken to change LSI.

### 4/5 — Good app

*2013-04-23*

Needs a conductivity input option, then 5 stars

### 5/5 — Great app

*2012-06-24*

Does what it says.  I use it daily.  Better than working it out on paper!

## Frequently asked questions about LSI Pool and Spa Calculator

### What is the Langelier Saturation Index calculator?

The Langelier Saturation Index calculator is a tool that helps pool owners and professionals determine the balance of their pool water. It calculates the LSI based on pH, temperature, total alkalinity, and calcium hardness levels, ensuring a healthy swimming environment.

### How accurate are the Langelier Saturation Index calculations?

The app provides instant and accurate calculations of the LSI. Users can track changes over time to make necessary adjustments to their pool's water chemistry.

### Can I use the Langelier Saturation Index calculator offline?

Yes, the Langelier Saturation Index calculator does not require network connectivity, allowing you to perform calculations anywhere.

### What devices support the Langelier Saturation Index calculator?

The Langelier Saturation Index calculator is a universal app that supports iPhone, iPod Touch, and iPad devices, ensuring compatibility across various screen sizes.

### How often is the Langelier Saturation Index calculator updated?

The latest version of iOS is supported, and the app was last updated on July 6, 2023, indicating regular maintenance and updates.

### What is the price of the Langelier Saturation Index calculator?

The Langelier Saturation Index calculator is available for a one-time purchase of $0.99.

### Can I share my pool water calculations?

Yes, you can send your calculations or conversions by email directly from the app. Additionally, you can export your data to CSV format for further analysis.

### What is the age rating for the Langelier Saturation Index calculator?

The Langelier Saturation Index calculator has an age rating of 4+, making it suitable for a wide range of users.

## Version history (last 5 releases)

### 9.6 — 2026-10-07

You put care into every pool and spa visit, and those careful checks matter. Thank you for using LSI Pool and Spa Calculator. This update adds customer contacts, linked properties, and a site map, with more ways to review and share your work.

CUSTOMER CONTACTS IN ONE PLACE

- Add local customers with names, companies, phone numbers, email addresses, and notes.
- Search customers before a visit.
- Edit customer details as arrangements change.
- Add contacts manually without device Contacts access.
- Choose which device contacts to copy into the app.
- Keep local edits separate from the contacts stored on your device.

MORE USEFUL CONTACT IMPORTS

- Bring in a primary mailing address along with names, phone numbers, and emails.
- Keep additional addresses and available contact details in searchable notes.
- Reimport an existing contact to fill a missing address or add missing detail notes.
- Preserve changes you have made to local customer fields.
- Use selected-contact access on supported devices.
- Adjust contact access from the import screen.

LINK CUSTOMERS TO THEIR PROPERTIES

- Connect several pools, spas, or service sites to one customer.
- Choose a customer while adding or editing a site.
- Link existing sites while adding or editing a customer.
- Give each property its own address and service notes.
- Open a customer's details to see their linked sites.
- Keep sites and reading history saved if you delete a customer.

NEW SITE MAP

- Find Site Map in Stats.
- See pins for saved properties whose addresses can be located.
- Use a site's own address, with its customer's address as a fallback.
- Tap a pin to open the customer and their linked properties.
- Choose a site when customers share a mapped location.
- Open an unlinked property's editor from its pin.
- Search All Sites, including properties that still need an address.
- Correct an address and retry a lookup when a site cannot be located.
- Use the map without giving the app access to your current location.

REPORTS THAT INCLUDE CUSTOMER DETAILS

- Export customers, sites, or water readings as CSV files.
- Create PDF reports for those lists.
- Include addresses and customer links in site and contact reports.
- Share a quick calculation, saved reading, or statistics summary as a PDF.
- Choose the information you need for a customer, colleague, or your own files.

BACKUPS THAT KEEP THINGS CONNECTED

- Complete backups now include local customers, property addresses, and customer-to-site links.
- Restore those links when importing a complete backup.
- Continue importing older supported backups.
- Skip exact duplicate items rather than adding the same information again.
- Keep local customer edits while adding missing address details and notes.
- See import results showing how many items were added or skipped.

EASIER HISTORY REVIEW

- Search and sort individual site and record lists from Stats.
- Filter individual readings by result category.
- Use the compact Records sort control to choose a field and direction.
- Continue through Records and Spreadsheet as more saved readings load while you scroll.
- Review charts and minimum, maximum, and average readings to compare visits.
- Keep a selected record beside the list on iPad.

EVERYDAY TOOLS WITH CLEARER GUIDANCE

- Find Contacts, Import & Export, and Habits & Progress from More.
- Choose Light, Dark, or system appearance in Settings.
- Set the temperature unit you prefer for new readings and Quick Calc.
- Check updated Help for customer links, maps, reports, and backups.

Spreadsheet review, backup imports, sharing individual reports, and printing require LSI Pro. Your free version still supports up to five saved readings.

### 9.5 — 2026-09-10

You keep the water work moving, and good records make that work easier to trust later. Thank you for using LSI Water Service Log and for putting it to work on real pool and spa service days.

This update focuses on a cleaner app flow, stronger Pro access handling, better settings, clearer help, and a More screen that keeps important tools easier to reach.

Navigation is now simpler:

- Quick Calc now has its own fourth tab for faster access.
- Spreadsheet review moved into More where it fits with the rest of the review tools.
- More now brings Pro, Spreadsheet, Import and Export, Settings, Help, and About together.
- The More screen has a cleaner pool-style look with simple rows and clear labels.
- Settings and About are now easy to find from More.

Pro access is clearer and easier to act on:

- The Pro screen is more compact at the top.
- Purchase options are available directly from the Pro view.
- Restore purchase access remains available.
- Locked features now guide users to the correct Pro screen.
- Pro status copy is easier to understand.
- Purchase messages use clearer App Store wording.

Purchase access is also more dependable:

- The app now checks current App Store purchase status when it launches.
- Local cached purchase state is treated only as a temporary helper.
- Cached purchase access is cleared when verification is not available.
- Unverified purchase information no longer keeps features unlocked.
- Pro access updates more directly after purchase, restore, or entitlement changes.

Settings gained useful everyday controls:

- Added an Appearance setting.
- Choose Follow System to use the device appearance.
- Choose Light when you prefer a bright app look.
- Choose Dark when you prefer a darker app look.
- Keep default units for new records and Quick Calc.
- Clear recent calculator inputs without affecting saved records.
- Check the installed app version from Settings.
- Use the new manual Check for Updates button.
- Open the App Store from the update result when a newer version is available.

About and Help are more user-friendly:

- About now includes clear AS IS and no warranty language.
- Help text now focuses on what users do in the app.
- Cleaned up wording so screens read more naturally.
- Calculator notes explain the result in plain language.
- Import and export wording now talks about backups and spreadsheet files.
- Quick Calc copy now explains local use without technical storage details.
- Support, privacy, and terms links remain grouped in Settings and About.

Import, export, and sharing text is cleaner:

- Export Spreadsheet File now uses clearer wording.
- Records Backup and Full Backup labels are easier to understand.
- Import Backup now matches the backup language used elsewhere.
- Export status messages are easier to read.
- Import success messages now refer to saved items from backup.
- Backup error messages are less technical.

Record and calculator wording also got polish:

- The help flow now starts with Add Site, Records, and More.
- Record editing instructions are clearer.
- Quick Calculator guidance now matches the current actions menu.
- Formula help keeps the useful calculation details without extra clutter.
- Local calculation text now feels more natural.

This version also tightens the finished app experience across the screens users see most. The result is a cleaner app for pool and spa water balance tracking, faster everyday navigation, more reliable Pro access, clearer settings, and better wording throughout.

Thanks again for using LSI Water Service Log. This update is meant to make every reading, record, backup, and review step feel more direct while keeping the app focused on practical pool and spa service work.

### 9.4 — 2026-08-22

You keep the water work moving, and good records make that work easier to trust later. Thank you for using LSI Water Service Log and for putting it to work on real pool and spa service days.

This update focuses on a cleaner app flow, stronger Pro access handling, better settings, clearer help, and a More screen that keeps important tools easier to reach.

Navigation is now simpler:

- Quick Calc now has its own fourth tab for faster access.
- Spreadsheet review moved into More where it fits with the rest of the review tools.
- More now brings Pro, Spreadsheet, Import and Export, Settings, Help, and About together.
- The More screen has a cleaner pool-style look with simple rows and clear labels.
- Settings and About are now easy to find from More.

Pro access is clearer and easier to act on:

- The Pro screen is more compact at the top.
- Purchase options are available directly from the Pro view.
- Restore purchase access remains available.
- Locked features now guide users to the correct Pro screen.
- Pro status copy is easier to understand.
- Purchase messages use clearer App Store wording.

Purchase access is also more dependable:

- The app now checks current App Store purchase status when it launches.
- Local cached purchase state is treated only as a temporary helper.
- Cached purchase access is cleared when verification is not available.
- Unverified purchase information no longer keeps features unlocked.
- Pro access updates more directly after purchase, restore, or entitlement changes.

Settings gained useful everyday controls:

- Added an Appearance setting.
- Choose Follow System to use the device appearance.
- Choose Light when you prefer a bright app look.
- Choose Dark when you prefer a darker app look.
- Keep default units for new records and Quick Calc.
- Clear recent calculator inputs without affecting saved records.
- Check the installed app version from Settings.
- Use the new manual Check for Updates button.
- Open the App Store from the update result when a newer version is available.

About and Help are more user-friendly:

- About now includes clear AS IS and no warranty language.
- Help text now focuses on what users do in the app.
- Cleaned up wording so screens read more naturally.
- Calculator notes explain the result in plain language.
- Import and export wording now talks about backups and spreadsheet files.
- Quick Calc copy now explains local use without technical storage details.
- Support, privacy, and terms links remain grouped in Settings and About.

Import, export, and sharing text is cleaner:

- Export Spreadsheet File now uses clearer wording.
- Records Backup and Full Backup labels are easier to understand.
- Import Backup now matches the backup language used elsewhere.
- Export status messages are easier to read.
- Import success messages now refer to saved items from backup.
- Backup error messages are less technical.

Record and calculator wording also got polish:

- The help flow now starts with Add Site, Records, and More.
- Record editing instructions are clearer.
- Quick Calculator guidance now matches the current actions menu.
- Formula help keeps the useful calculation details without extra clutter.
- Local calculation text now feels more natural.

This version also tightens the finished app experience across the screens users see most. The result is a cleaner app for pool and spa water balance tracking, faster everyday navigation, more reliable Pro access, clearer settings, and better wording throughout.

Thanks again for using LSI Water Service Log. This update is meant to make every reading, record, backup, and review step feel more direct while keeping the app focused on practical pool and spa service work.

### 9.3 — 2026-07-17

You keep the water work moving, and good records make that work easier to trust later. Thank you for using LSI Water Service Log and for putting it to work on real pool and spa service days.

This update focuses on a cleaner app flow, stronger Pro access handling, better settings, clearer help, and a More screen that keeps important tools easier to reach.

Navigation is now simpler:

- Quick Calc now has its own fourth tab for faster access.
- Spreadsheet review moved into More where it fits with the rest of the review tools.
- More now brings Pro, Spreadsheet, Import and Export, Settings, Help, and About together.
- The More screen has a cleaner pool-style look with simple rows and clear labels.
- Settings and About are now easy to find from More.

Pro access is clearer and easier to act on:

- The Pro screen is more compact at the top.
- Purchase options are available directly from the Pro view.
- Restore purchase access remains available.
- Locked features now guide users to the correct Pro screen.
- Pro status copy is easier to understand.
- Purchase messages use clearer App Store wording.

Purchase access is also more dependable:

- The app now checks current App Store purchase status when it launches.
- Local cached purchase state is treated only as a temporary helper.
- Cached purchase access is cleared when verification is not available.
- Unverified purchase information no longer keeps features unlocked.
- Pro access updates more directly after purchase, restore, or entitlement changes.

Settings gained useful everyday controls:

- Added an Appearance setting.
- Choose Follow System to use the device appearance.
- Choose Light when you prefer a bright app look.
- Choose Dark when you prefer a darker app look.
- Keep default units for new records and Quick Calc.
- Clear recent calculator inputs without affecting saved records.
- Check the installed app version from Settings.
- Use the new manual Check for Updates button.
- Open the App Store from the update result when a newer version is available.

About and Help are more user-friendly:

- About now includes clear AS IS and no warranty language.
- Help text now focuses on what users do in the app.
- Cleaned up wording so screens read more naturally.
- Calculator notes explain the result in plain language.
- Import and export wording now talks about backups and spreadsheet files.
- Quick Calc copy now explains local use without technical storage details.
- Support, privacy, and terms links remain grouped in Settings and About.

Import, export, and sharing text is cleaner:

- Export Spreadsheet File now uses clearer wording.
- Records Backup and Full Backup labels are easier to understand.
- Import Backup now matches the backup language used elsewhere.
- Export status messages are easier to read.
- Import success messages now refer to saved items from backup.
- Backup error messages are less technical.

Record and calculator wording also got polish:

- The help flow now starts with Add Site, Records, and More.
- Record editing instructions are clearer.
- Quick Calculator guidance now matches the current actions menu.
- Formula help keeps the useful calculation details without extra clutter.
- Local calculation text now feels more natural.

This version also tightens the finished app experience across the screens users see most. The result is a cleaner app for pool and spa water balance tracking, faster everyday navigation, more reliable Pro access, clearer settings, and better wording throughout.

Thanks again for using LSI Water Service Log. This update is meant to make every reading, record, backup, and review step feel more direct while keeping the app focused on practical pool and spa service work.

### 9.2 — 2026-05-28

This update focuses on faster workflow, clearer record handling, and stronger data portability for day-to-day pool and spa service operations.

What’s new in this version:
- Added a full tabbed app structure for Records, Add Site, Stats, Spreadsheet, Export, Quick Calc, and Help.
- Improved the record-first workflow so new measurements can be started, edited, and saved with fewer taps.
- Added better draft handling when creating a new reading from the Records tab.

Records improvements:
- Added record search across site name, date text, and notes.
- Added segmented date sorting so you can switch between newest-first and oldest-first views.
- Added swipe actions to duplicate existing records quickly.
- Added swipe actions to share a single record from the list.
- Added delete confirmation to reduce accidental data loss.
- Improved empty-state messaging for no records and no search results.

Calculator and input updates:
- Improved quick entry flow for TDS, water temp, calcium hardness, alkalinity, and pH.
- Added stronger input validation boundaries for chemistry values.
- Improved error messages for invalid or out-of-range entries.
- Added updated LSI category messaging and color-coded result states.
- Preserved recent input defaults to reduce repetitive typing.

Add Site enhancements:
- Added reusable site name and notes storage.
- Added “Choose saved site” picker flow for faster form filling.
- Added save confirmation toast so technicians get immediate feedback.
- Improved keyboard dismissal and form usability.

Stats enhancements:
- Added per-site stats navigation from the main Stats list.
- Added minimum, maximum, and average summaries for major chemistry metrics.
- Added one-tap share output for site statistics.
- Improved stats layout readability for on-site review.

Spreadsheet upgrades:
- Added spreadsheet-style grid browsing for dense record review.
- Added column header sorting interactions.
- Added initial load optimization and incremental “Load Next Rows” paging.
- Added loading state UI to clarify when rows are being prepared.
- Added device-aware batch sizing for iPhone and iPad performance.

Export and backup improvements:
- Added CSV export for GameStats records.
- Added JSON export for GameStats records.
- Added full database JSON export for broader backup needs.
- Added JSON import flow with confirmation step before applying data.
- Added import result messaging to show object count after completion.

Quick Calc tab updates:
- Added standalone local quick calculator mode with no Core Data dependency.
- Added local persistence for the most recent calculation result.
- Added reset, randomize, and share actions in the Quick Calc menu.
- Added saved timestamp visibility for the last local calculation.

Help and About updates:
- Added expanded in-app Help sections covering app flow and key screens.
- Added About screen details for version/build display.
- Added privacy and terms messaging in the About view.

Under-the-hood work:
- Improved asynchronous loading patterns in Spreadsheet view.
- Improved state handling for list/detail behavior across compact and regular layouts.
- Added utility extensions and test coverage for sorting, stats, spreadsheet behavior, and help/about content.

Quality and workflow polish:
- Improved contextual help text so new technicians can onboard faster.
- Refined wording and labels across multiple screens for clearer in-field use.
- Updated sharing and export flows to make handoff to clients and managers more consistent.

Thanks to everyone using LSI Calc DB in the field. This release is centered on reliability, faster daily logging, and easier reporting for pool water balance work.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-23.*