About this app
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/
App Store Screenshots
Latest App Store Release Notes
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.
App Store Information
- App Store category: Utilities
- Genres: Utilities, Business
- Availability: Free
- Current version: 9.6
- Requires: iOS 17.6 or later
- Content rating: 4+
- Last updated: 2026-10-07
Developed by Verosocial. App details can change; verify the current App Store listing before publication.