Comparison

LSI Pool and Spa Calculator vs PoolBuddy

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

Head to head
About

LSI Pool and Spa Calculator

This app helps pool and spa professionals meticulously track water chemistry, customer details, and service records. It calculates the Langelier Saturation Index, logs visits with notes, and organizes customer and property information. Visualize trends with charts and generate reports for comprehensive service management.

Highlights
  • Calculate LSI with detailed water chemistry inputs
  • Log service visits with notes and treatments
  • Organize customer and property contact information
  • Map saved pool and spa locations
  • Review historical water chemistry data with charts
  • Quick calculation without saving readings
  • Generate PDF reports and export data as CSV
Features
Read full description

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/

About

PoolBuddy

Features
Read full description

PoolBuddy is the assistant that takes care of your pool or spa water. It measures, understands and acts: it tells you exactly what to add and how much. • Measure with a photo. Photograph the test strip (next to the bottle, so the light doesn't fool it) or your drop test kit, and the AI reads chlorine, pH and the rest of the parameters. • Instant diagnosis and doses. Know whether the water is safe to swim in, and the approximate doses to fix it, in grams or ounces. • AI advisor. It analyzes your whole pool —parameters, weather and season— and gives you clear recommendations. • Advanced chemistry. Water balance (LSI index), combined chlorine, stabilizer adjustment, salt and more. • Built-in weather. It uses the sun, UV and temperature of your location to fine-tune filtration and alert you. • Everything in one place. "What to do today", tasks, product inventory, filter pressure, season opening/closing checklists, costs and trend charts. • Bluetooth probe input and Apple Watch app. Doses are approximate estimates; always follow the product label instructions.

Screenshots

LSI Pool and Spa Calculator3 screens
PoolBuddy3 screens

Verdict

The call

The clearest difference is in-app purchases: PoolBuddy at none against LSI Pool and Spa Calculator's 2. PoolBuddy also leads on update cadence (every 4 days vs every 6 weeks). On price, ads, device support and iOS requirement 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. LSI Pool and Spa Calculator sells 2 in-app purchases, starting at $1.99 per month. PoolBuddy asks for nothing beyond the download.

UpkeepUpdate frequency

LSI Pool and Spa Calculator ships an update every 6 weeks, PoolBuddy every 4 days. The most recent releases landed on November 1, 2026 and October 31, 2026 respectively.

Scorecard2 real differences · 8 level
LSI Pool and Spa Calculator versus PoolBuddy: the parameters behind the verdict, then further details
ParameterLSI Pool and Spa CalculatorPoolBuddy
PriceFreeFree
Rating5.0 (1 ratings) — better—
Positive reviews76.9% of reviews—
Number of ratings1 — better—
Update frequencyEvery 6 weeksEvery 4 days — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhone, iPadiPhone, Apple Watch
Requires iOS17.617.0 — better
Further details — not scored
Size7 MB3 MB
Age rating+44+
DeveloperVerosocial StudioNetknow

In-app purchases

2 purchases

LSI Pool and Spa Calculator

Subscriptions1
  • LSI Calculators pro Monthly$1.991 Month
One-time1
  • LSI Calculators pro lifetime$14.99
None

PoolBuddy

No in-app purchases

Questions

Is LSI Pool and Spa Calculator free?
LSI Pool and Spa Calculator is free to download, with in-app purchases available.
Is PoolBuddy free?
PoolBuddy is free to download, with no in-app purchases.
Do LSI Pool and Spa Calculator or PoolBuddy have ads?
Neither LSI Pool and Spa Calculator nor PoolBuddy shows ads.
Which is updated more often, LSI Pool and Spa Calculator or PoolBuddy?
LSI Pool and Spa Calculator ships an update every 6 weeks, and PoolBuddy every 4 days. Most recently, LSI Pool and Spa Calculator was updated on November 1, 2026 and PoolBuddy on October 31, 2026.

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