Water Test Calculator vs Pool Math, feature-by-feature, honest
Pool Math is the long-standing standard. Water Test Calculator is the new entrant that auto-calculates CYA-adjusted targets. Here’s the feature-by-feature breakdown, plus where each app wins.
Last updated: 2 June 2026
Pool Math (developed by the Trouble Free Pool community) has been the de facto standard for residential pool chemistry calculations for over a decade. It’s free on the web, $5 on mobile, and uses the Pickens-method chemistry that almost every other serious pool calculator references.
Water Test Calculator is the new entrant, launching in approximately 10 days. The chemistry foundation is the same, also Pickens-method, also TFP-referenced, but the workflow and UX are different. This page is the feature-by-feature comparison, written by the Water Test Calculator team (so be aware of the bias and read with that in mind).
Quick feature comparison
| Feature | Pool Math | Water Test Calculator |
|---|---|---|
| Chemistry methodology | TFP / Pickens method | TFP / Pickens method (same) |
| CYA-adjusted FC target | Manual, look up the chart | Automatic, calculated from CYA reading |
| Multi-pool profiles (chlorine + salt + spa) | Single profile (limited) | Dedicated profiles for each pool type |
| Volume memory across sessions | Re-enter for each calc | Enter once, used forever |
| Guided testing mode (for new users) | No, calculator only | Yes, step-by-step workflow |
| Smart notifications (chemical wait times) | No | Yes |
| History tracking | Manual log entry | Auto-saved test history |
| Offline functionality | Yes | Yes |
| Free tier | Web fully free, mobile $5 one-time | Free with ads, premium subscription tiers |
| Community / forum integration | Excellent (TFP forum) | None at launch |
| UI / visual design | Dated but functional | Modern glass-morphism design |
| Camera-based test strip scanning | No | Roadmap (v2.0+) |
Where Pool Math wins
One-time pricing model
Pool Math is $5 one-time on mobile, free forever on the web. No subscription. For owners who hate subscription apps (a legitimate stance), Pool Math is the clear winner.
TFP community integration
Pool Math is tied to the Trouble Free Pool forum, the largest pool chemistry community online. If you have a complex problem, you can post on TFP and get expert answers from real pool chemists within hours. Water Test Calculator has no equivalent at launch.
Battle-tested chemistry
Pool Math has been running for years. Edge cases have been refined. Bugs have been caught. Water Test Calculator is new, even with the same chemistry methodology, the implementation will have rough edges in v1.0.
Web version availability
Pool Math has a free web version that works without any app install. Useful for desktop chemistry calculation or one-off use.
Where Water Test Calculator wins
Automatic CYA-based targeting
This is the killer feature. Pool Math requires you to know the CYA chart and apply it manually, if your CYA is 80, you should know to target FC of 9 ppm, not 1–3 ppm. Most Pool Math users don’t, and dose for the chart on the back of the chlorine bottle (1–3 ppm) regardless of CYA.
Water Test Calculator does the CYA math automatically. You never look up the chart. You never apply the wrong target.
Guided mode for new pool owners
Pool Math assumes you know what you’re doing, test, enter readings, dose. For a first-summer pool owner, this is overwhelming. Water Test Calculator’s Guided Mode walks through the testing workflow step by step, ensuring you don’t skip critical parameters.
Volume memory
Enter your pool’s volume once. The app uses it for every future calculation. Pool Math expects you to enter it on each calculation, small friction that compounds across a season.
Multi-pool profiles
Many Australian households have a pool + spa. Water Test Calculator maintains separate chemistry profiles for each, with different parameters and targets. Pool Math can handle multiple pools but with limited differentiation.
Smart notifications
After you add muriatic acid, when can you swim? After you shock, when is the FC down to safe range? Water Test Calculator tracks chemical wait times and notifies you. Pool Math is a calculator, it doesn’t track ongoing chemistry over time.
The pricing comparison
| Period | Pool Math | Water Test Calculator |
|---|---|---|
| Year 1 | $5 (one-time) | Free or $79.99 (annual) |
| Year 5 | $5 total | $0 free OR $399.95 annual subscription OR $299.99 lifetime |
| Year 10 | $5 total | $0 free OR $799.90 annual OR $299.99 lifetime |
The honest takeaway: if you’re an experienced pool owner who’d use only the calculator functionality, Pool Math at $5 is the better economic choice over a decade. The additional features of Water Test Calculator premium ($79.99/year or $299.99 lifetime) are valuable mainly to less-experienced owners or households with multiple pools/spas.
Who should choose which
Stay with Pool Math if:
- You’re an experienced pool owner who knows the CYA chart and applies it manually.
- You’re an active TFP forum participant.
- You prefer one-time pricing over subscriptions.
- You only need a calculator, not a guided testing experience.
Switch to Water Test Calculator if:
- You’re a new pool owner and want guidance through the testing workflow.
- You’ve kept forgetting to apply CYA math correctly and have had repeat algae problems.
- You maintain a pool AND a spa and want separate profiles.
- You want smart notifications for wait times and re-tests.
- You value modern UI/UX.
Or use both
Pool Math and Water Test Calculator use the same chemistry, so they give the same answers. Using both as a cross-check is reasonable, confirm Water Test Calculator’s dose recommendations against Pool Math’s, especially during the first month of use to build confidence in the math.
Sources & references
- Trouble Free Pool, ABCs of Pool Water Chemistry
- Richard Falk, The Chlorine/CYA Relationship
- ANSI/APSP-11, Water Quality Standards in Public Pools
Frequently asked questions
Is Water Test Calculator better than Pool Math?
Depends on the user. For experienced pool owners who know the CYA chart, Pool Math at $5 one-time is fine. For new pool owners or households with multiple pools/spas, Water Test Calculator’s guided workflow and automatic CYA targeting are meaningful improvements. Same underlying chemistry.
Can I import my Pool Math data into Water Test Calculator?
Not at v1.0 launch. Manual import (re-entering recent readings) is the only option. Cross-app data import is on the roadmap for v1.1+.
Does Pool Math use the same chemistry as Water Test Calculator?
Yes, both apps use the Trouble Free Pool community’s Pickens-method chemistry. The dose recommendations match. The difference is workflow and UI.
Is the $5 Pool Math worth it over the free web version?
Yes for regular use, the mobile app is offline-capable, doesn’t show ads, has better data storage. The free web version is fine for one-off calculations or occasional desktop use.
Will Water Test Calculator replace Pool Math?
Not for everyone. Pool Math will remain a strong choice for experienced TFP-aligned users. Water Test Calculator is positioned for users who want the chemistry handled for them, guided workflow, automatic CYA targeting, multi-pool profiles. Different value propositions.
When is Water Test Calculator launching?
Approximately 10 days from publication of this page. iOS App Store and Google Play. Sign up for the launch list to be notified.
Get the launch alert + free checklist
Water Test Calculator launches on iOS and Android in ~10 days. Free with ads. Premium unlocks unlimited history, smart notifications, and ad-free testing.