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 organize water testing readings, customer details, and service visits. It calculates the Langelier Saturation Index, tracks historical data, and generates service reports for clients.

Highlights
  • Calculate LSI from water parameters
  • Track customer and site details
  • Log service visits and chemical actions
  • View historical data and charts
  • Generate service reports
  • Schedule future visits
Features
Read full description

You put care into every pool and spa you look after. Thank you for using LSI Pool and Spa Calculator. Your attention to water testing matters, and this app helps you keep readings, customer details, and service visits organized. Whether you maintain your own spa or look after several properties, bring your water balance calculator and service log together. Enter measured values, check the Langelier Saturation Index, and keep a useful record for your next visit. CHECK POOL AND SPA WATER BALANCE - Calculate LSI from measured pH, water temperature, calcium hardness, total alkalinity, and total dissolved solids. - See the calculated saturation pH and a result category. - Review whether readings suggest a scale or corrosion tendency. - Work in Fahrenheit or Celsius and convert the entered temperature when switching units. - Find the formula, measurements, and result ranges in Help. KEEP READINGS YOU CAN FIND AGAIN - Save measurements under reusable pool, spa, and property names. - Record dates and notes about water condition, treatments, or follow-up work. - Search saved history by site, result category, or notes. - Sort readings, correct saved inputs, and recalculate after an edit. - Duplicate a record for another visit. - Review a reading beside the records list on wider iPad layouts. PLAN AND RECORD SERVICE VISITS - Schedule visits for a saved pool or spa site. - Add a technician, visit status, and completed-work checklist. - Record actual chemical actions, service observations, and customer notes. - Link a saved water reading or enter fresh measurements for the visit. - Preview a service report before saving. - Keep an unfinished new visit as a local draft. - Note the next service or retest date and book a separate visit when ready. KEEP CUSTOMERS AND SITES CONNECTED - Save customer names, companies, phone numbers, emails, addresses, and notes. - Add customers manually or choose contacts to copy from Apple Contacts. - Link several sites to one customer and give each site its own address. - Keep local contact edits separate from device Contacts. - Find mapped sites using their address or a linked customer's address. - Search the site list even when a property still needs an address. REVIEW CHANGES OVER TIME - Explore charts for LSI, pH, temperature, hardness, alkalinity, and TDS. - Compare minimum, maximum, and average measurements. - Review history by customer or individual site. - Filter readings by result category. - Use Quick Calc for a check outside saved site history. - Set a weekly testing goal and review milestones in Habits & Progress. USE INPUT TOOLS THAT FIT THE JOB - Reset a form or search from its three-line menu. - Share current field labels and values, including an unfinished form. - Expand Details when you need guidance and keep notes in their fields. - Enable Sample Data or Randomize in Settings when you want practice inputs. Both start off. - Choose Light, Dark, or system appearance. TAKE YOUR RECORDS WITH YOU - Export readings, sites, contacts, or service visits as CSV or PDF. - Save JSON backups and review processing limits before relying on a backup. - Use Apple Watch for independent LSI calculations, local saved readings, and sharing. Watch readings do not sync with iPhone. The free iPhone app supports up to five saved readings. LSI Pro adds a larger reading allowance, spreadsheet review, backup import, and individual text and PDF reports. Watch calculation, saving, and sharing are free. Use reliable water tests alongside equipment and treatment guidance. LSI describes saturation tendency; it does not calculate chemical doses. Keep testing, keep good notes, and head into your next visit prepared. 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 Calculator4 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 5 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 5 weeks, PoolBuddy every 4 days. The most recent releases landed on November 6, 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 reviews78.6% of reviews—
Number of ratings1 — better—
Update frequencyEvery 5 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
Size8 MB3 MB
Age rating4+4+
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 5 weeks, and PoolBuddy every 4 days. Most recently, LSI Pool and Spa Calculator was updated on November 6, 2026 and PoolBuddy on October 31, 2026.

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