Best pool chemistry apps (honest comparison)
If you test with a drop kit and like to understand the math, Pool Math ($7.99 a year) is the most complete independent calculator. If you want to be taught step by step and don't mind $49.99 a year, Swim University's app is a good fit. Free brand apps work best with that brand's own strips and products. We checked 10 apps in the U.S. App Store on September 29, 2026. Our own app is not released yet, and we list its limits too.
On this page (8 sections)
How we compared (criteria, date checked)
We are not neutral: we are building a pool and hot tub app of our own, the Pooldex app. To keep this page useful anyway, every fact below comes from a public source you can check, with a date, and we list what the other apps do well.
- Price, ratings, and last update: Apple's public App Store lookup for the U.S. store, read on September 29, 2026. Ratings change daily.
- Features: each app's own App Store description. Where we could not confirm a feature there, the table says "not confirmed".
- What users report: public App Store reviews in the U.S. store, read in September 2026. Quotes are short and dated. A review is one person's experience, not a test result.
- What we did not do: we did not buy subscriptions, create accounts, or run lab tests of any app's dosing.
The criteria reviewers mention most are the ones in the table: do you need an account, can you enter results from any test, does it handle hot tubs, can you see your history, and what does it cost.
Comparison table
| App (developer) | Price | Ratings (average) | Last update | Test entry | Tied to a brand |
|---|---|---|---|---|---|
| Clorox Pool (BioLab) | Free | 29,019 (4.59) | Jan 29, 2025 | Scan strips or enter liquid or strip results | Yes: its analysis is for Clorox Pool&Spa products |
| Leslie's - Pool Care (Leslie's) | Free | 14,168 (4.62) | Aug 27, 2026 | In-store tests and AccuBlue Home | Retailer app |
| Pool Time ClearPool Expert (BioLab) | Free | 5,632 (4.73) | Aug 1, 2023 | Pool Time ClearPool Expert strips; description also lists liquid or DPD kit results | Yes (Home Depot) |
| HTH Test to Swim (Solenis) | Free | 3,943 (4.68) | Jul 6, 2026 | Scans HTH 6-way strips; spa strip chart | Yes; myHTH account to save history |
| AquaChek Connect (Hach) | Free | 1,233 (3.21) | Sep 28, 2026 | Photo of Select Connect strips, or manual; no registration | Strip brand |
| Orenda (Hasa) | Free | 476 (4.72) | Sep 21, 2026 | Enter results; dosing by LSI | Enzyme brand; calculator is general |
| Pooli (Pooli, Inc.) | Free; paid Pool Club sold on its website | 369 (4.60) | Sep 11, 2026 | Manual; strip scan with Pool Club | No |
| Pool Math (TroubleFreePool) | Free; Premium $7.99/year | 287 (3.63) | May 3, 2026 | Manual, built around drop kits | No |
| Pool Care by Swim University (Gazzini Ventures) | $49.99/year, 7-day trial | 224 (4.60) | Sep 9, 2026 | Manual | No |
| Pool-Calculator (Pool and Spa Resources) | $4.99 one-time | 630 (4.15) | Oct 6, 2025 | Any strip or kit; works offline | No |
| Pooldex (us) | Free core; Plus $24.99/year, $14.99 Season Pass, or $59.99 lifetime (planned) | Not released | — | Manual, any strip or drop kit | No |
Prices are what the U.S. App Store listed on 2026-09-29; Swim University's price is from its in-app purchase list and matches a July 2026 review. Pooli's club is sold outside the App Store, so we don't quote its price here.
| App | Account needed | Hot tub | History |
|---|---|---|---|
| Clorox Pool | Yes, per reviews (for example, "scanner is behind a login screen", Feb 27, 2026) | Reviews report a 1,000-gallon minimum (latest July 2026) | Last 10 analyses (description) |
| HTH Test to Swim | myHTH account to save history (description) | Spa strip chart (description) | With account |
| AquaChek Connect | No (description) | not confirmed | Pool test history (description) |
| Pooli | not confirmed | Yes: pools or spas, multiple bodies of water | Graphs over time (description) |
| Pool Math | not confirmed | Spa configurations with Premium; older reviews ask for bromine and spa ranges | Unlimited with Premium; free users report one saved test |
| Swim University | not confirmed | Hot tub listed (description); a 2026 review wanted a second body of water | not confirmed |
| Pooldex (planned) | No | Yes, 50–1,500 gal, chlorine or bromine | Log: last 30 days free; charts 2 weeks free; full history in Plus |
Brand apps (free, tied to their products)
The apps with the most ratings are free because they are made by chemical and strip brands. That is a fair trade if you already use the brand: the scanner is tuned to its strips and the recommendations name its products. The trade-offs show up in reviews.
- Clorox Pool has by far the most ratings (29,019) and a scan-to-test feature. Its description says the analysis is designed for Clorox Pool&Spa products and that history shows your last 10 analyses. When we checked, it had not been updated since January 29, 2025. Hot tub owners often criticize it. One July 11, 2026 review says it "requires pools to be at least 1000 gallons."
- HTH Test to Swim scans HTH 6-way strips and adds a matching chart for HTH spa strips. You need a myHTH account to save history. Reviews are split between people who like the scanner and people who get different readings from the same strip.
- AquaChek Connect needs no registration, which is rare among brand apps, but it works with the brand's Select Connect strips. Its reviews in July and August 2026 are dominated by crash reports, such as "App crashes immediately after taking photo" (August 1, 2026). The developer shipped an update on September 28, 2026 that mentions strip-reading fixes.
- Pool Time ClearPool Expert (Home Depot's Pool Time line) says it is compatible only with its own strips (while also listing liquid and DPD kit results) and had not been updated since August 1, 2023.
- Leslie's is a store app first: rewards, ordering, store locator, and your in-store and AccuBlue Home test history. It is useful if you test at Leslie's, less so as a standalone calculator.
- Orenda is a free dosing calculator built around the LSI (water balance), with few negative reviews. It is detailed, and its LSI focus can feel technical if you are new.
Independent calculators
- Pool Math by TroubleFreePool is the enthusiast's tool: calculators for every parameter including borates and CSI (calcite saturation index), "effects of adding", maintenance tracking, and Siri Shortcuts. Premium ($7.99 a year) unlocks unlimited log history, reminders, cloud sync, multiple pools, and CSV import and export. The main complaint is the free tier: a September 20, 2026 review says "You get exactly one test and then after that you cannot change." We look at it in detail on our Pool Math alternative page.
- Pool Care by Swim University explains as it doses: a plan in the right order, wait times between chemicals, problem guides, and videos. Reviewers praise its support. It costs $49.99 a year after a 7-day trial, with no free mode; one July 7, 2026 review calls "7 day trial and then $50 a year" overpriced.
- Pooli has the most features: custom targets per pool or spa, inventory, graphs, CSI, an AI assistant, and task lists. Hot tub owners rate it well. Strip scanning needs its Pool Club, sold on its website. Some reviewers find it complex.
- Pool-Calculator is a $4.99 one-time purchase that works offline with any test, including CSI and a what-if calculator, and lets you set your own ranges. Some reviews report problems after updates.
Our app: strengths and limits
The Pooldex app is not in the App Store yet. Here is what we are building and where it will fall short, so you can judge it against the list above when it launches.
What we focus on:
- No account. Open it and enter a test.
- Any strip or drop kit, entered by hand in a few taps; strip readings are shown as ranges, not fake decimals.
- Doses for the product and strength you own, by active ingredient, with no brand promotion.
- Full hot tub support: 50 to 1,500 gallons, chlorine or bromine, teaspoons and grams.
- Free: dose calculations for one pool or hot tub, the last 30 days of your test log, basic reminders, iCloud sync, and a CSV export of your data.
- The same tested formulas as this website's calculators, published on our methodology page.
Limits at launch:
- No ratings or track record yet.
- No strip scanner in the first version; a camera helper that compares your strip with your own bottle's chart is planned later.
- Full history, charts beyond 2 weeks, more than one pool, PDF reports, and extra widgets are in the paid Plus tier: $24.99 a year with a 14-day free trial, $14.99 for a 6-month Season Pass that does not renew, or $59.99 once for Lifetime (planned U.S. prices; no monthly plan).
- iPhone first. No Android.
- No sensor or equipment integration, and no CSI; our pH model does not account for CO2 loss after dosing, so every acid step says "retest".
The app page has more on the app, including what comes with Free and Plus.
Which to choose
- You use one brand's strips and chemicals and like scanning: that brand's free app. Keep a drop kit for when the scanner and the water disagree.
- You use a drop kit (Taylor K-2006 or similar) and follow the Trouble Free Pool method: Pool Math, with Premium if you want your full log.
- You are new and want to be taught, with human support: Swim University's app, if $49.99 a year is fine.
- You want every feature and several pools or spas: Pooli.
- You want a one-time purchase that works offline: Pool-Calculator.
- You have a hot tub under 1,000 gallons, don't want an account, or use strips from any store: that's who we are building for. Until the app launches, the calculators on this site are free and use the same formulas.
Whatever you pick, the app is only as good as your test. Our guide to reading test strips covers when strips are good enough and when to use drops.
FAQ
What is the best pool chemical calculator app?
It depends on how you test. For drop-kit users who want detailed math, Pool Math is the most complete independent calculator. For beginners who want guidance and support, Swim University's app. For brand-strip users, that brand's free app. All three have trade-offs listed above, checked September 29, 2026.
What is the most accurate way to test pool chemicals?
A FAS-DPD drop kit for chlorine, plus the kit's drop tests for pH, alkalinity, calcium, and stabilizer. FAS-DPD reads free and combined chlorine in 0.2 or 0.5 ppm steps (Taylor), and the CDC notes that test strips are less accurate than DPD kits. Strips and phone scanners are fine for quick checks.
What is the best digital pool chemical tester?
We have not tested digital testers ourselves, so we don't rank them. If you shop for one, check that it reads free chlorine separately from total chlorine, covers stabilizer (CYA), states its accuracy, and uses reagents you can buy easily. Whatever it reads, you can enter the numbers into any calculator, including ours.
Sources
- Apple, iTunes Search API lookup (U.S. store), read 2026-09-29: itunes.apple.com
- App Store pages: Clorox Pool, Leslie's, Pool Time ClearPool Expert, HTH Test to Swim, AquaChek Connect, Orenda, Pooli, Pool Math, Pool Care by Swim University, Pool-Calculator
- App Store customer reviews (U.S. public reviews feed), read September 2026; review dates are given next to each quote.
- CDC, Home pool and hot tub water treatment and testing: cdc.gov
- Taylor Technologies, How FAS-DPD tests for free and combined chlorine values: taylortechnologies.com