# NPC Pro > Pool professional's tool for water chemistry, LSI calculation, and plaster startup guides. (iPhone/iPad app by National Plasters Council, Inc.) - Source: https://appshunter.io/ios/app/npc-pro/id1273077384 (this page in markdown: same URL + `.md`) - Developer: [National Plasters Council, Inc](https://appshunter.io/developer/1273077383) - Category: Business - Price: Free (on sale, was $4.99) - Age rating: 4+ - Requires: iOS 15.0 · 84 MB - Languages: American English, European Spanish - Released: 2017-09-04 - Data updated: 2026-06-01 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/npc-pro/id1273077384/reviews.md ## What is NPC Pro? NPC Pro LSI Calculator & Startup Guide – The Ultimate Water Chemistry Tool for Pool Professionals! Developed by the National Plasterers Council (NPC), the NPC Pro LSI Calculator & Startup Guide is the essential app for pool professionals, technicians, and service providers. Whether you’re calculating the Langelier Saturation Index (LSI) to ensure balanced water chemistry or following proper startup procedures for new plaster finishes, this app simplifies the process with accuracy and ease. Key Features: - LSI Calculator – Quickly determine water balance to prevent scaling, etching, and plaster degradation. - Water Chemistry Guide – Get precise recommendations for pH, alkalinity, calcium hardness, and more. - Startup Procedures – Follow NPC’s step-by-step plaster startup guide for long-lasting, durable finishes. - Easy Data Input – Enter key pool chemistry values and get instant LSI results. - Professional-Grade Accuracy – Designed for pool contractors, service techs, and water chemistry experts. - User-Friendly Interface – Simplifies complex calculations for effortless use on the job. - Ask The Expert – If you have questions we have answers, use our ask the expert form to get answers to your toughest questions from the NPC community experts. - Connect. Engage. Explore. In addition to the tools, NPC Pro offers you access to find members, stream podcasts, access technical resources, connect with NPC social media and more. - Podcasts Why Use the NPC Pro LSI Calculator & Guide? Balanced water chemistry is crucial to maintaining a beautiful, durable swimming pool finish. The LSI Calculator ensures your water is within the ideal range, preventing costly repairs and extending the life of pool surfaces. The Startup Guide provides step-by-step instructions to correctly introduce new plaster finishes, avoiding common issues like discoloration or surface roughness. Whether you’re a pool professional, service technician, or pool owner looking for precise water chemistry management, this app is your go-to tool! Download the NPC Pro LSI Calculator & Startup Guide today and take the guesswork out of pool chemistry! Pool Owners • Pool Professionals • Tech Resources • Education Affiliations: American Shotcrete Association Independent Pool and Service Association California Pool and Spa Association The Association for Pool and Spa Professionals American Concrete Institute American National Standards Institute Institute for Code Council Our Mission The National Plasterers Council will continue to be the utmost authority in the preparation, application, materials, start-ups and preservation of cementitious pool interior finishes. The NPC will collaborate with other associations and serve the industry through research, education, promotion, and certification of all segments of the pool industry including pool owners, the pool service providers, plasterers, manufacturers, specifiers, remodelers, architects, and builders. ## Key features - LSI Calculator for water balance - Water chemistry recommendations - Plaster startup procedures guide - Easy data input for instant results - Professional-grade accuracy - Ask the Expert feature - Access to podcasts and technical resources ## Recent user reviews (10 of 10) All indexed reviews: https://appshunter.io/ios/app/npc-pro/id1273077384/reviews.md ### 5/5 — Great pool app *2026-02-15* A great app that’s not commercially branded to a company. NPC is a great group ### 1/5 — Plagiarism of Orenda *2025-06-16* This app is clearly a copycat of Orenda, without giving them credit. Even the settings menu is identical in formatting and spelling. Blatant plagiarism. AND the math doesn’t align. It would be one thing if you gave credit to them (like PoolBrain does), but no. Seems like intellectual property theft to me. ### 5/5 — Great resource for all in swimming pool industry! *2025-02-25* This is such a great app and resource. LSI calculator, Start up instructions, NPC Technical Library and downloadable files & start up card. Get all the expertise of the National Plasterers Council at your fingertips with ease! ### 5/5 — Great new app *2025-02-05* The new app that NPC just put out is really great. So many features. Thank you NPC. Love the calculator and podcasts. ### 3/5 — Not sure it’s accurate *2022-07-04* Not sure it’s accurate with lower alkalinity and higher PH levels at 50 ppm borate. The LSI goes negative as the PH approaches 8.5 for my pool conditions of 80 ppm alkalinity, 290 CH, 50 ppm borate, 60 CYA, 86 Fahrenheit, 4500 tds. Seems maybe the borate correction on alkalinity allows alkalinity to go negative at higher PH levels? Is this correct? ### 5/5 — Great App *2021-02-16* I own a pool service company in AZ and I use this app all the time to get my LSI readings at each pool. Even though it doesn’t give you suggested amounts of chems to use to adjust the numbers that’s ok for now, although I’d like to see that calculator on here someday. It’s dead in accurate every time. ### 1/5 — Not for testing pools! *2020-09-01* This app is not designed to calculate any sort of pool treatment ( not like google recommends), it only displays the end condition of your water chemistry based on the input values your give it. It wides not tell you chemicals to add to bring your pool back to a (clear water) state. ### 5/5 — My bad. *2019-02-06* App great ### 5/5 — Now good to go on iOS 12 *2018-10-23* With the latest update the app is working as advertised. Back in business, thanks! I will add that the arrow graphic at the top is pretty much unreadable with way too small fonts. But the rest of the app is good. **Developer response:** We apologize, there was an issue with the latest version of iOS, but it has been corrected. Please update the app and let us know if there are still any issues. thank you. ### 1/5 — Doesn’t work on iPhone *2018-10-03* Input boxes are stacked on top of each other. Can’t use **Developer response:** We apologize, there was an issue with the latest version of iOS, but it has been corrected. Please update the app and let us know if there are still any issues. thank you. ## Frequently asked questions about NPC Pro ### What is the main function of NPC Pro? NPC Pro's main function is to help pool professionals calculate the Langelier Saturation Index (LSI) for balanced water chemistry and to provide step-by-step startup procedures for new plaster finishes. It aims to simplify complex calculations and ensure the longevity of pool surfaces. ### Does NPC Pro have ads? No, NPC Pro does not contain advertisements. It is a free application developed by the National Plasterers Council. ### What kind of water chemistry data does NPC Pro provide recommendations for? NPC Pro provides precise recommendations for key water chemistry parameters including pH, alkalinity, and calcium hardness. This helps users maintain optimal water balance to prevent issues like scaling and etching. ### How does NPC Pro help with plaster startup procedures? NPC Pro offers NPC's official step-by-step plaster startup guide. This ensures that new plaster finishes are introduced correctly, which is crucial for achieving long-lasting, durable surfaces and avoiding common problems like discoloration. ### Can I ask experts questions through NPC Pro? Yes, NPC Pro features an 'Ask The Expert' form. This allows users to submit their toughest questions and receive answers from the NPC community experts, providing valuable support for professionals. ### What other resources are available within NPC Pro besides the calculators? Beyond its core calculation tools, NPC Pro offers access to stream podcasts, technical resources, and connections to NPC social media. It also allows users to find members and engage with the NPC community. ### On which devices can I use NPC Pro? NPC Pro is available for iPhone, iPad, and iPod devices. It is designed to be a convenient tool for professionals on the go. ### How frequently is NPC Pro updated? NPC Pro was last updated on February 15, 2026, with version 2.1.1. This indicates a commitment to maintaining and improving the application's features and accuracy. ## Version history (last 5 releases) ### 2.1.1 — 2026-02-15 Updated LSI calculator 3 new volume calculators NPC site integration Pool Startup procedures Technical bulletins New entry save data interface Flex your finish NPC podcast links and player Flex your finish Push notifications ### 2.0.0 — 2025-02-05 Revamped NPC App ### 1.2 — 2021-09-03 Issue Fixes Added Carbonate Alkalinity calculations ### 1.1 — 2018-10-17 Bug Fixes & Improvements ### 1.0 — 2017-09-04 No release notes. ## Apps similar to NPC Pro | App | Rating | Price | Category | | --- | --- | --- | --- | | [MiCar Driver](https://appshunter.io/ios/app/micar-driver/id1580559660) | — | Free | Business | | [DG1 Management](https://appshunter.io/ios/app/dg1-management/id1580537700) | — | Free | Business | | [DEXIS Hub](https://appshunter.io/ios/app/dexis-hub/id1584308040) | — | Free | Business | | [LSI Calc DB Water Balance Log](https://appshunter.io/ios/app/lsi-calc-db-water-balance-log/id373769371) | 1.0 (1) | Free | Business | | [Leak Logic](https://appshunter.io/ios/app/leak-logic/id1584957894) | 5.0 (3) | Free | Business | | [CIEC](https://appshunter.io/ios/app/ciec/id1578402980) | — | Free | Business | ## Related topics [npc pro](https://appshunter.io/ios/topics/npc-pro) · [npc](https://appshunter.io/ios/topics/npc) · [langelier saturation index](https://appshunter.io/ios/topics/langelier-saturation-index) --- *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 2026-06-01.*