A Pool Math alternative
Pool Math is a strong calculator for drop-kit users, and its Premium tier costs $7.99 a year. The most common complaints in its App Store reviews are a free tier that saves only one test, manual backups, device sync, and canceling. The Pooldex app (coming soon to the App Store) takes the same approach of matching free chlorine (FC) to stabilizer (CYA). Version 1.0 is free, with the full test log, iCloud sync, and reminders included.
On this page (7 sections)
What Pool Math is great at
Pool Math comes from TroubleFreePool, a large pool-owner community, and many of its users follow that community's method: a proper drop test kit, liquid chlorine, and chlorine targets based on stabilizer. According to its App Store description (checked September 29, 2026), it offers:
- calculators for free chlorine, pH, alkalinity, calcium, salt, stabilizer, borates, and CSI (calcite saturation index);
- an "effects of adding" calculator that shows what a product will do before you pour it;
- maintenance tracking (backwashing, filter pressure, salt cell percentage, flow rate) and weather on your logs;
- a bleach price calculator, a summary page, and, in its latest update (May 3, 2026), swimmer-load logs and Siri Shortcuts.
Long-time users say so in their reviews. A September 21, 2026 four-star review says "The ability to log treatments, chemicals and see the effects of adding chemicals is helpful." If Pool Math works for you, there is no reason to switch.
Common complaints (from App Store reviews, dated)
In our September 2026 collection of 202 Pool Math reviews from the U.S. App Store (2017–2026), 84 were 1–3 stars. The most frequent topics among them were crashes or "not working" (25), the paywall, subscription, or canceling (20), and "broken by an update" (20). Reviews are individual experiences, and some are years old; here are the recurring ones, newest first:
| Complaint | Examples (date, stars) |
|---|---|
| Free version saves only one test | "You get exactly one test and then after that you cannot change." (Sep 20, 2026, 1★). Similar reports on Aug 21, 2026; Jun 2, 2026; Jul 7, 2025; Feb 3, 2025. |
| Hard to cancel | "Way too hard to cancel." (Jun 15, 2026, 1★) |
| App and desktop give different doses | App suggested 8 oz of acid, the desktop version 56 oz, and the larger amount was needed (Jul 10, 2026, 1★, paraphrased) |
| iPad freezes on entry | Fields freeze on iPad after years of use (Jun 29, 2026, 3★, paraphrased) |
| Data lost on a new phone | "Apparently you need to manually backup and restore data" (Sep 25, 2025, 1★) |
| Sync between devices | Can't get sync across devices, so one adult handles all chemicals (Jul 26, 2025, 3★, paraphrased) |
| Hot tubs treated as small pools | "A hot tub is not a small pool." (Nov 21, 2022, 4★); no bromine option (Aug 6, 2020, 2★). Older reviews; current spa features not confirmed by us. |
On canceling, to be fair: like every App Store subscription, Pool Math Premium is canceled in your iPhone's Settings (tap your name, then Subscriptions; see Apple Support). Its description says the same. Pooldex 1.0 has no subscriptions, so there is nothing to cancel.
Feature table
| Feature | Pool Math | Pooldex 1.0 |
|---|---|---|
| Price | Free; Premium $7.99/year | Free, every feature included; no in-app purchases, no ads |
| Dose calculations | Free | Free, pool and hot tub |
| Test log | Unlimited with Premium; free users report one saved test | Full history, free |
| Cloud backup and sync across devices | Premium | Free, through your own iCloud |
| Reminders | Premium | Free (local notifications) |
| Charts | Summary page; a June 2026 review asks for monthly and yearly charts | Charts with target bands and dose markers, full history, free |
| Pools and spas | Unlimited configurations with Premium | Unlimited, free |
| Hot tub specifics | Spa configurations (Premium); bromine not confirmed | Hot tub mode 50–1,500 gal, chlorine or bromine, no stabilizer by default (CDC), teaspoons and grams |
| CSV | Test log CSV import and export (Premium) | CSV export of all data, free; no import in version 1.0 |
| Chemistry depth | Borates, CSI, SWG %, effects of adding | Borates, LSI (no CSI), learns your chlorine jug's real strength from retests |
| Account | not confirmed | None |
| Siri / Shortcuts | Yes | Yes (App Intents) |
| Community | TroubleFreePool forum | None; support through the app and our website |
| Track record | In the App Store since 2017; 287 ratings, 3.63 average | Not released yet; no ratings |
Pool Math facts from its App Store description and listing, read 2026-09-29; "free users report one saved test" is from reviews, not the description. Our column describes version 1.0, which is coming soon to the App Store; see the app page.
Same method, different app: FC/CYA logic
If you follow the TroubleFreePool method, you won't have to relearn anything. The core idea, that the free chlorine you need rises with stabilizer, is also in the CDC's Model Aquatic Health Code (MAHC 2024 Annex, 5.7.3.1.1.2). Our engine uses its own published formula based on that principle: minimum FC is 7.5% of CYA (5% for salt chlorine generators), never below 2 ppm with stabilizer. We don't give a shock level from CYA: ratio-based shock levels are above the swim limit on pool chlorine labels, so for shock we point you to your product's label directions.
| CYA | Liquid or tablet chlorine: min / target | Salt generator: min / target |
|---|---|---|
| 30 ppm | 2.5 / 2.5–4.5 ppm | 2 / 2–4 ppm |
| 40 ppm | 3 / 3–5 ppm | 2 / 2–4 ppm |
| 50 ppm | 4 / 4–6 ppm | 2.5 / 2.5–4.5 ppm |
| 60 ppm | 4.5 / 4.5–6.5 ppm | 3 / 3–5 ppm |
| 70 ppm | 5.5 / 5.5–7.5 ppm (CYA above our range) | 3.5 / 3.5–5.5 ppm |
| 80 ppm | 6 / 6–8 ppm (CYA above our range) | 4 / 4–6 ppm |
Pool Math's own targets may differ slightly; we did not copy its tables. The MAHC Annex notes that the EPA has not approved pool products for use above 4 ppm while people swim, which conflicts with the higher targets at high CYA. We show both and recommend CYA at 30–50 ppm for manually chlorinated pools so the target stays near the label range. Always follow the product label. It is a violation of federal law to use a pesticide product in a manner inconsistent with its labeling.
Where the sources disagree and why we chose these numbers is on the methodology page; to see your own targets, enter your CYA in the pool chlorine levels calculator.
Import your log (CSV)
Your history is yours, whichever app you use. Pool Math lists test log CSV import and export as a Premium feature, so if you subscribe, export your log before you stop using it and keep the file.
The Pooldex app exports all your data to CSV for free, in plain columns (date, source, FC, TC, CC, pH, TA, CH, CYA, salt, temperature, note) that open in Numbers or Excel. Importing another app's CSV is not in the first version. If you want to bring a Pool Math log over, tell us through the app support page: we use requests to decide what to build next.
FAQ
Is Pool Math app free?
It is free to download, and the calculators work without paying. Premium, $7.99 a year in the U.S. App Store as of September 29, 2026, adds unlimited log history, reminders, cloud sync and backup, multiple pools and spas, and CSV import and export. Several reviews from 2025 and 2026 report that the free version saves only one test.
Is Pool Math Premium worth it?
If you use a drop kit, follow the TroubleFreePool method, and log every test, $7.99 a year is inexpensive for what it adds. Weigh the reported issues first: device sync and iPad problems in some 2025–2026 reviews, and the need to cancel through your iPhone's subscription settings.
Does Pool Math work for hot tubs?
Its description lists spa configurations for Premium subscribers. Older reviews (2020–2022) asked for bromine and spa-specific ranges; we could not confirm what is supported today. For hot tub targets and doses, see our hot tub care section.
Sources
- Pool Math by TroubleFreePool, App Store listing and description (U.S.), read 2026-09-29: apps.apple.com
- Apple, iTunes Search API lookup (price, ratings, version date): itunes.apple.com
- Pool Math customer reviews, U.S. public reviews feed (dates next to each quote): itunes.apple.com
- Apple Support, Cancel a subscription from Apple: support.apple.com
- CDC, Model Aquatic Health Code 2024, Annex (chlorine and CYA): cdc.gov (PDF)