Your pool, tracked — free, private, no account
Log a test and get the whole picture: every number judged against the right target for your pool, the exact dose for anything out of range, and the trends that catch a problem building before it turns your water green. It all lives on your device — no account, nothing uploaded, and your history doesn't vanish when you leave the page.
Add to your home screen: tap Share, then Add to Home Screen — it works offline once installed.
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The Chlorine Showdown
Same free-chlorine boost, four ways — and the hidden cost each one quietly adds. Pick how much FC you want to add and see who wins.
Preview any other dose
See every number a move touches before you commit — the secondary effects included.
How long will your salt cell run — and last?
Most run-time calculators stop at the chlorine per day. We also tell you what your output setting is doing to the cell's lifespan — because the cell is the expensive part, and sizing up makes it last.
Why this beats a paper log (or the pool store's printout)
A single test result tells you today; a log tells you the story. The tracker keeps your history so you can see your CYA creeping up from trichlor tablets, your pH always drifting high, or your chlorine trending toward the floor — the patterns that a one-off reading (or a pool-store water test that ends in a shopping cart) completely hides. And every reading is checked against the target for your pool, not a generic chart, because the right free-chlorine level depends entirely on your CYA.
The FC/CYA relationship, done for you
The number most people get wrong is free chlorine, because they treat it as a fixed target. It isn't — it scales with your stabilizer. The tracker reads your FC against your CYA using the same FC/CYA chart the rest of Pool School uses, so it knows the difference between "below the floor, algae risk" and "running a little high, totally fine." Learn the why in how chlorine and CYA actually work.
It's private by design
There's no login because there's no server keeping your data. Your pool profile and every test you log are stored only in this browser, on this device — the logbook never phones home. The one exception is opt-in and obvious: when you tap Coach my pool, that snapshot is sent to our AI to write your plan, and we don't store it. Everything else stays local — which also means it's gone if you clear your browser data, so use Export a backup to save a copy or move it to your phone. Free, ad-light, and we never sell you a bottle you don't need.
Pair it with the rest of Pool School
Dosing calculator → ·Water balance (LSI/CSI) → ·Diagnose a problem → ·All of Pool School →
FAQ
Is there a free pool log app that doesn't need an account?
Yes — the Pool Tracker on this page is free and requires no account, no email, and no download. You set up your pool once (volume, chlorine type, surface), then log each test. Everything is saved right in your browser on your device, so nothing is uploaded to any server, and unlike some free logbooks your history is not lost when you navigate away. You can export a backup file any time to move it to another device.
What pool water numbers should I track?
Six core numbers: free chlorine (FC), combined chlorine (CC), pH, total alkalinity (TA), calcium hardness (CH), and cyanuric acid (CYA, stabilizer) — plus salt if you run a salt system. The most important relationship is FC to CYA: the right chlorine level is not a fixed number, it scales with your CYA, so the tracker judges your free chlorine against your CYA using the standard FC/CYA chart rather than a one-size-fits-all target.
How do I know what my pool chemistry should be?
It depends on your pool. The right free-chlorine level is set by your CYA; the right calcium hardness depends on whether your surface is plaster, vinyl, or fiberglass; and a salt pool runs a higher CYA than a chlorine pool. The tracker takes your pool profile and judges each logged reading against the correct target for that pool — telling you whether each number is in range, needs a nudge, or needs fixing now, and giving the exact dose to correct it.
Does the tracker tell me how much of each chemical to add?
Yes. When a reading is out of range, the tracker gives a concrete dose for your pool's volume — how much liquid chlorine to raise FC to target, baking soda to raise alkalinity, calcium chloride to raise hardness, stabilizer to raise CYA, salt to raise salt, or muriatic acid to bring pH down. The dosing uses the same figures as our chemical calculator, which are calibrated to established pool-chemistry references. Always start with what you tested — retest before adding more.
Does my pool data get uploaded or shared?
The logbook itself stores your pool profile and test history only in your own browser (localStorage) on the device you use — no account, nothing sent to a server, nothing shared. The one exception is opt-in: if you tap "Coach my pool," that snapshot of your numbers is sent to our AI to generate the plan, and we do not store it afterward. Everything else stays on your device, which also means it is erased if you clear your browser data — use the Export a backup button to keep a copy.
How often should I test and log my pool?
In swim season, test a couple of times a week, and always after heavy rain, a big pool party, or a heat wave — the things that burn through chlorine. Logging each test is what turns single readings into trends, so you can catch a problem building (like CYA slowly climbing from trichlor tablets, or pH always drifting up) before it becomes a green pool or a fight to rebalance.
The Pool Tracker is a convenience layered on your own testing — measure your real numbers with a good drop-based kit first, and treat every dose as a starting point to retest against. Targets and doses use the same figures as our calculators and guides. Pool School is free and independent.